An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollutio...

LQ

Lê Quỳnh Anh

27 tháng 11 2017

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful subtances known...

Đọc tiếp

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful subtances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and notrigen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature’s output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as as city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a subtance to be a pollutant; in fact, the numerial value tells us little until we know how much of an increase this represents over ther concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

According to the passage, human-generated air pollution in localized regions ________.

A. can be dawrfed by nature’s output of pollutants

B. can overwhelm the natural system that removes pollutants

C. will damage areas outside of the localized regions

D. will react harmfully with natural pollutants

#Mẫu giáo

1

DH

Dương Hoàn Anh

27 tháng 11 2017

Đáp án B.

Key words: human-generated, localized regions.

Câu hỏi: Theo bài khóa, đâu là ý đúng về các chất ô nhiễm không khí do con người gây ra ở các vùng chuyên môn hóa?

Clue: “In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles”: Ở những vùng như vậy, chất thải của con người quá nhiều và có thể tạm thời quá tải áp đảo chương trình thanh lọc tự nhiên của chu trình.

Phân tích: Chu trình được nói đến ở trên là chu trình thanh lọc nhằm loại bỏ khí ô nhiễm. Do đó, ta chọn đáp án B. can overwhelm the natural system that removes pollutants: có thể áp đảo hệ thống tự nhiên loại bỏ các chất gây ô nhiễm. Các đáp án khác không phù hợp:

A. can be dwarfed by nature’s output of pollutants: có thể bị làm ít đi bởi những chất gây ô nhiễm ngoài tự nhiên.

C. will damage areas outside of the localized regions: sẽ gây hại khu vực bên ngoài một nơi nhất định.

D. will react harmfully with natural pollutants: sẽ phản ứng gây hại đến những chất ô nhiễm tự nhiên.

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LQ

Lê Quỳnh Anh

21 tháng 5 2019

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34. An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth...

Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area.

What does the passage mainly discuss?

A. The economic impact of air pollution.

B. What constitutes an air pollutant.

C. How much harm air pollutants can cause.

D. The effects of compounds added to the atmosphere.

#Mẫu giáo

1

DH

Dương Hoàn Anh

21 tháng 5 2019

Chọn B.

Đáp án là B.

Giải thích: Bài văn chủ yếu bàn về :

A. Tác động về mặt kinh tế của ô nhiễm không khí

B. Những gì hợp thành 1 tác nhân ô nhiễm không khí

C. Mức độ nguy hại mà chất ô nhiễm gây ra

D. Ảnh hưởng của các hợp chất bị thêm vào không khí

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LQ

Lê Quỳnh Anh

21 tháng 6 2017

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34. An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth...

Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area.

The word "adversely" in the first paragraph is closest in meaning to _______.

A. negatively

B. quickly

C. admittedly

D. considerably

#Mẫu giáo

1

DH

Dương Hoàn Anh

21 tháng 6 2017

Chọn A.

Đáp án là A.

Giải thích: Từ “adversely: 1 cách tiêu cực/bất lợi” gần nghĩa nhất với từ nào sau đây?

A. negatively: tiêu cực

B. quickly: nhanh chóng

C. admittedly: thừa nhận rằng

D. considerably: đáng kể

Dịch: An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials ADVERSELY.

(Một chất gây ô nhiễm không khí được định nghĩa là một hợp chất được đem trực tiếp hoặc gián tiếp vào khí quyển bởi con người ở một khối lượng gây ảnh hưởng đến con người, động vật, thực vật hay các nguyên liệu khác một cách tiêu cực.)

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LQ

Lê Quỳnh Anh

28 tháng 7 2017

An air pollutnt is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful subtances known...

Đọc tiếp

An air pollutnt is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful subtances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and notrigen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature’s output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as as city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a subtance to be a pollutant; in fact, the numerial value tells us little until we know how much of an increase this represents over ther concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

The word “adversely” in the first paragraph is closet in meaning to ________.

A. negatively

B. quickly

C. admittedly

D. considerably

#Mẫu giáo

1

DH

Dương Hoàn Anh

28 tháng 7 2017

Đáp án A.

Key words: paragraph 1, adversely

Clue: “An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely”: Ô nhiễm không khí được định nghĩa như hợp chất thải trực tiếp hoặc gián tiếp bởi con người vào không khí với một lượng để ảnh hưởng tiêu cực đến con người, động vật, thảm thực vật hoặc nguyên liệu.

adversely (adv) = in a way that is negative and unpleasant and not likely to produce a good result.

Vậy adversely gần nghĩa nhất với A. negatively: một cách tiêu cực.

Các đáp án còn lại là sai:

B. quickly: nhanh chóng

C. admittedly: được thừa nhận

D. considerably: đáng kể

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LQ

Lê Quỳnh Anh

29 tháng 1 2017

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful subtances known...

Đọc tiếp

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful subtances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and notrigen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature’s output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as as city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a subtance to be a pollutant; in fact, the numerial value tells us little until we know how much of an increase this represents over ther concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

The word “These” in the second paragraph is closet in meaning to ________.

A. the various chemical reactions

B. the pollutants from the developing Earth

C. the compounds moved to the water or soil

D. the components in biogeochemical cycles

#Mẫu giáo

1

DH

Dương Hoàn Anh

29 tháng 1 2017

Đáp án D.

Key words: these, second paragraph, closet in meaning.

Clue: “…they became components in biogeochemical cycles. These serve as an air purification scheme by…”: … chúng trở thành thành phần trong chu trình sinh địa. Những chất này có vai trò như một chương trình thanh lọc không khí bằng cách …

Phân tích: “Chúng” ở đây là cụm danh từ được nhắc đến ngay trước đó. Vậy chọn đáp án D. the components in biogeochemical cycles.

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LQ

Lê Quỳnh Anh

11 tháng 10 2017

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful subtances known...

Đọc tiếp

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful subtances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and notrigen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature’s output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as as city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a subtance to be a pollutant; in fact, the numerial value tells us little until we know how much of an increase this represents over ther concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

For which of the following reasons can natural pollutants play an important role in controlling air pollution ?

A. They function as part of a purification process

B. They occur in greater quantities than oher pollutants

C. They are less harmful to living beings than other pollutants

D. They have existed since the Earth developed

#Mẫu giáo

1

DH

Dương Hoàn Anh

11 tháng 10 2017

Đáp án A.

Key words: natural pollutants, controlling air pollution, nature.

Câu hỏi: Dưới những lí do sau, đâu là lí do để chất gây ô nhiễm giữ vai trò quan trọng trong kiểm soát ô nhiễm không khí?

Clue: “Many of the more important air pollutants … are found in nature…they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil”: Nhiều trong số các chất ô nhiễm không khí … được tìm thấy trong tự nhiên …chúng trở thành thành phần trong chu trình sinh địa. Các chất này có vai trò như một kế hoạch thanh lọc không khí bằng cách cho phép hợp chất di chuyển từ không khí sang nước hoặc đất.

Phân tích: Từ Clue có thể tóm tắt lại là các chất gây ô nhiễm trong tự nhiên trở thành các chất hóa học khác, chất hóa học này lại tạo quy trình thanh lọc này. Chọn đáp án A. They function as part of a purification process.

Các đáp án khác:

B. They occur in greater quantities than other pollutants: Các chất này hình thành với khối lượng lớn hơn các chất ô nhiễm khác – Không có thông tin.

C. They are less harmful to living beings than other pollutants: Các chất này ít gây hại đến các sinh vật sống hơn các chất ô nhiễm khác – Không có thông tin.

D. They have existed since the Earth developed: Chúng đã tồn tại kể từ khi Trái Đất hình thành – Không phải là một vai trò của ô nhiễm không khí.

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LQ

Lê Quỳnh Anh

25 tháng 12 2018

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful subtances known...

Đọc tiếp

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful subtances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and notrigen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature’s output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as as city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a subtance to be a pollutant; in fact, the numerial value tells us little until we know how much of an increase this represents over ther concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

According to the passage, the numerical value of the concentration level of a substance is only useful if ________.

A. the other substances in the area are known

B. it is in a localized area

C. the natural level is also known

D. it can be calculated quickly

#Mẫu giáo

1

DH

Dương Hoàn Anh

25 tháng 12 2018

Đáp án C.

Key words: numerical value, concentration level.

Câu hỏi: Theo bài khóa, giá trị bằng con số của mức độ dồn lượng một chất sẽ chỉ hữu dụng khi nào?

Clue: “…the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level”

Phân tích: Ngay sau khi nhắc đến giá trị bằng con số, tác giả đưa ra ví dụ trong đó có sự xuất hiện của hai biến là “concentration level” và “natural level”. Do đó, để “concentration level” có ý nghĩa thì cũng phải biết “natural level”. Chọn đáp án C. the natural level is also known.

Các đáp án khác không phù hợp:

A. the other substances in the area are known: các chất khác trong tự nhiên được biết.

B. it is in a localized area: các chất có ở khu vực chuyên môn hóa.

C. it can be calculated quickly: nó phải được tính nhanh.

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LQ

Lê Quỳnh Anh

22 tháng 8 2019

Read the following passage and mark the letter A, B, C, or D on your answer answer to each of the questionsAn air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely . Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to...

Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer answer to each of the questions

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely . Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions. Many of more important air pollutants such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentrations of these pollutants were altered by various chemical reactions; they became components in biogeochemical cycle. Theseserve as an air purification scheme by allowing the compounds to move from the air to the water or soil on a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In this localized regions, human output may be dominant and may temporarily overload the natural purification scheme of the cycle. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, as a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

What does the passage mainly discuss?

A. The economic impact of air pollution

B. What constitutes an air pollutant

C. How much harm air pollutants can cause

D. The effects of compounds added to the atmosphere

#Tiếng anh thí điểm lớp 10

1

DH

Dương Hoàn Anh

22 tháng 8 2019

Đáp án: C

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LQ

Lê Quỳnh Anh

13 tháng 10 2018

Read the following passage and mark the letter A, B, C, or D on your answer answer to each of the questionsAn air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to...

Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer answer to each of the questions

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions. Many of more important air pollutants such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentrations of these pollutants were altered by various chemical reactions; they became components in biogeochemical cycle. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil on a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In this localized regions, human output may be dominant and may temporarily overload the natural purification scheme of the cycle. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, as a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

What does the passage mainly discuss?

A. The economic impact of air pollution

B. What constitutes an air pollutant

C. How much harm air pollutants can cause

D. The effects of compounds added to the atmosphere

#Tiếng anh thí điểm lớp 11

1

DH

Dương Hoàn Anh

13 tháng 10 2018

Đáp án C

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LQ

Lê Quỳnh Anh

4 tháng 3 2019

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34. An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth...

Đọc tiếp

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 30 to 34.

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.

Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area.

The word “These” in the second paragraph is closest in meaning to _______.

A. The various chemical reactions

B.The pollutants from the developing Earth

C.The compounds moved to the water or soil 6

D. The components in biogeochemical cycles

#Mẫu giáo

1

DH

Dương Hoàn Anh

4 tháng 3 2019

Chọn D.

Đáp án D.

Giải thích:

Từ "these" trong đoạn thứ hai là gần nhất trong ý nghĩa với__________:

A. Các phản ứng hóa học khác nhau

B. Các chất gây ô nhiễm từ trái đất đang phát triển

C. Các hợp chất chuyển đến nước hoặc đất

D. Các thành phần trong chu kỳ sinh địa hóa

Ý trong bài : “As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil.”

(Khi Trái đất phát triển, sự tập trung vào các nhân tố gây ô nhiễm này bị thay đổi bởi các phản ứng hoá học, chúng trở thành những phần tử nằm trong chy kỳ hoá sinh. Những phần tử này hoạt động như 1 chu trình làm sạch không khí bằng cách cho phép các hợp chất này di chuyển từ không khí sang nước hay đất.)

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