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Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.

Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.

The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.

In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world's weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.

The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.

Which of the following best describes the organization of the passage?

A. A general idea is introduced and several specific examples are given.

B. Two possible causes of a phenomenon are compared.

C. A problem is described and possible solutions are discussed.

D. A recommendation is analyzed and rejected.

1
30 tháng 10 2017

Đáp án C

Dịch nghĩa: Phương án nào miêu tả cấu trúc bài viết phù hợp nhất?

A. Một ý kiến chung được đưa ra và một vài ví dụ cụ thể được trình bày.

B. Hai nguyên nhân có thể xảy ra của một hiện tượng được so sánh.

C. Một vấn đề được trình bày và những giải pháp được bàn đến.

D. Một gợi ý được phân tích và phản đối.

Giải thích: Vấn đề cỏ dại mọc được bàn đến và giải pháp bàn đến là tác nhân hóa học và sinh học.

Bài dịch

Con người đã đấu tranh với cỏ dại từ khi bắt đầu ngành nông nghiệp. Làm hư hại vườn tược là một trong những tác hại còn nhẹ của cỏ dại - bất kỳ loài cây nào mọc lên ở chỗ mà chúng không được mong đợi. Chúng làm tắc nghẽn thủy lợi, phá hủy môi trường sống của động vật hoang dã, và cản trở nông nghiệp. Sự lan rộng của chúng loại bỏ các vùng chăn thả và chiếm một phần ba nguyên nhân của thiệt hại mùa vụ. Chúng cạnh tranh về ánh sáng, chất dinh dưỡng, và nước với những thực vật hữu ích.

Việc cần thiết phải kiểm soát cỏ dại toàn cầu đã được trả lời bởi ngành công nghiệp hóa chất,

thuốc diệt có hiệu quả và đôi khi cần thiết, nhưng một số vấn đề nghiêm trọng xảy ra, đặc biệt nếu sử dụng không đúng cách. Các hợp chất độc hại đe dọa động vật và sức khỏe cộng đồng khi chúng tích tụ trong các nhà máy thực phẩm, nước ngầm và nước uống. Chúng cũng gây tổn hại cho người lao động sử dụng chúng.

Trong những năm gần đây, ngành công nghiệp hóa học đã giới thiệu một số loại thuốc diệt cỏ thân thiện với hệ sinh thái hơn. Tuy nhiên, chỉ có hóa chất thì không thể giải quyết được vấn để cỏ dại trên toàn thế giới. Do đó, các nhà khoa học đang khám phá khả năng diệt có tự nhiên của các sinh vật sống, chủ yếu là côn trùng và vi sinh vật.

Các tác nhân sinh học đang sử dụng đầu thân thiện với môi trường và không có hại cho con người. Chúng có thể được lựa chọn tùy theo khả năng có thế tấn công các mục tiêu được ngắm đến và giữ lại các loại cây trồng mà không gây ảnh hưởng. Ngược lại, một số hóa chất hiệu quả nhất thì lại giết chết hầu như tất cả những cây mà chúng tiếp xúc với, chỉ chừa lại những cây kháng thuốc tự nhiên hoặc đã được biến đổi gen để kháng thuốc. Hơn nữa, một số tác nhân sinh học có thế chỉ cần dùng một lần duy nhất, sau đó không cần thiết phải dùng thêm. Còn hóa chất thường phải sử dụng nhiều lần trong suốt thời kì phát triển.

Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight,...
Đọc tiếp

Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.

Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.

The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.

In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world's weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.

The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.

Which of the following is NOT given as an advantage of using biological agents over chemical herbicides?

A. They are safer for workers.

B. They are less likely to destroy desirable plants.

C. They are more easily available.

D. They do not have to be used as often.

1
4 tháng 3 2017

Đáp án C

Dịch nghĩa: Câu nào sau đây không phải là một lợi ích của việc sử dụng tác nhân sinh học so với tác nhân hóa học?

A. An toàn cho sử dụng                               B. chúng ít khả năng làm hại những cây tốt

C. chúng có sẵn hơn.                                   D. Chúng không cần được sử dụng thường xuyên.

Giải thích: Phương án A, B và D đều được để cập trong bài, nhưng câu hỏi hỏi về KHÔNG nên chúng ta chọn C. Thông tin nằm ở đoạn 4 “The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. Furthermore, a number of biological agents can be administered only once”

Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight,...
Đọc tiếp

Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.

Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.

The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.

In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world's weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.

The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.

Which of the following statements about the use of chemical agents as herbicides would the author most likely agree?

A. It is occasionally required

B. It is safe but inefficient.

C. It should be increased

D. It has become more dangerous recently.

1
16 tháng 6 2018

Đáp án A

Dịch nghĩa: Câu nào nói về việc sử dụng chất hóa học như thuốc diệt cỏ mà tác giả dễ đồng ý nhất?

A. Thỉnh thoảng nó được cần đến                         B. Nó an toàn nhưng không hiệu quả.

C. Nó cần được tăng lên.                                      D. Dạo này nó đã trở nên nguy hiểm hơn.

Giải thích: Thông tin nằm ở đoạn 1 “Its herbicides are effective and sometimes necessary, but some pose serious problems”

Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight,...
Đọc tiếp

Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.

Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.

The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.

In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world's weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.

The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.

The word "marring" in bold is closest in meaning to ________.

A. spoiling

B. planting

C. dividing

D. replacing

1
25 tháng 8 2018

Đáp án A

Dịch nghĩa: Từ “marring” - làm hư hại in đậm gần nghĩa nhất với ___________.

A. làm tổn hại        B. trồng       C. phân chia          D. thay thế

Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight,...
Đọc tiếp

Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.

Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.

The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.

In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world's weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.

The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.

Which of the following terms does the author define in the first paragraph?

A. weeds

B. nutrients 

C. wildlife habitats 

D. grazing area

1
8 tháng 11 2018

Đáp án A

Dịch nghĩa: Thuật ngữ nào được tác giả định nghĩa trong đoạn 1?

A. cỏ dại                                                              B. chất dinh dưỡng

C. môi trường sống tự nhiên                                  D. đồng cỏ

Giải thích: Thông tin nằm ở đoạn 1 “Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted”.

Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight,...
Đọc tiếp

Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.

Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.

The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.

In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world's weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.

The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.

The word "innate" is closest in meaning to _____________.

A. effective

B. organic

C. natural

D. active

1
30 tháng 4 2019

Đáp án C

Dịch nghĩa: Từ “innate” - bẩm sinh gần nghĩa nhất với ___________.

A. hiệu quả B. hữu cơ    C. tự nhiên   D. tích cực

Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight,...
Đọc tiếp

Read the following passage and mark the letter A, B, tr or I) to indicate the correct answer to each of the questions from 36 to 42.

Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds - any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede fanning. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.

The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.

In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world's weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.

The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.

With what topic does this passage primarily deal?

A. The importance of the chemical industry.

B. The dangers of toxic chemicals.

C. A proposal to ban the use of all herbicides.

D. Advantages of biological agents over chemical ones.

1
6 tháng 6 2018

Đáp án D

A. Tầm quan trọng của nền công nghiệp hóa chất.

B. Sự nguy hiểm của chất hóa học độc hại

C. Yêu cầu cấm sử dụng thuốc diệt cỏ

D. Lợi ích của việc sử dụng tác nhân sinh học so với tác nhân hóa học.

Giải thích: Đoạn 1 nói về ảnh hưởng xấu của cỏ dại, đoạn 2 nói về chất hóa học tác động xấu, đoạn 3 chuyển ý và đoạn 4 nói về mặt tốt của tác nhân sinh học. Như vậy nhìn lại toàn bộ thì mục đích chính là so sánh để làm nôi bật lợi ích của việc dùng tác nhân sinh học.

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 37.  Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds – any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They...
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 37.

  Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds – any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.

The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.

  In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world’s weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.

The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.

Which of the following statements about the use of chemical agents as herbicides would the author most likely agree?

A. It has become more dangerous recently.

B. It is occasionally required.

C. It is safe but inefficient.

D. It should be increased.

1
5 tháng 9 2017

Đáp án B

 Câu nào trong những câu sau đây về việc sử dụng các tác nhân hóa học như chất diệt cỏ tác giả có thể đồng ý?

 A. Gần đây đã trở nên nguy hiểm hơn.

 B. Nó thỉnh thoảng cần thiết.

 C. Nó an toàn nhưng không hiệu quả.

 D. Nó nên được tăng lên.

Thông tin: The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary (Nhu cầu kiểm soát cỏ dại toàn cầu đã được hồi đáp chủ yếu bởi ngành công nghiệp hoá chất. Thuốc diệt cỏ có hiệu quả và đôi khi cần thiết)

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 37.  Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds – any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They...
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 37.

  Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds – any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.

The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.

  In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world’s weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.

The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.

The word ‘marring’ in bold is closest in meaning to

A. planting

B. spoiling 

C. dividing

D. replacin

1
15 tháng 7 2019

Đáp án B

Từ ‘marring’ in đậm gần nghĩa nhất với 

A. trồng 

B. làm hỏng 

C. phân chia  

D. thay thế

Dịch bài đọc:

Con người đã chống cỏ dại từ khi bắt đầu nông nghiệp. Làm hỏng vườn của chúng ta là một trong những ảnh hưởng nhẹ nhàng của cỏ dại - bất kỳ loài cây nào phát triển nơi chúng không cần thiết. Chúng làm tắc nghẽn đường dẫn nước, phá huỷ môi trường sống của động vật hoang dã và cản trở việc nuôi trồng. Sự lây lan của chúng sẽ xoá bỏ các khu vực chăn thả và chiếm một phần ba lượng mất mùa. Chúng cạnh tranh ánh sáng mặt trời, chất dinh dưỡng, và nước với cây trồng hữu ích.

Nhu cầu kiểm soát cỏ dại toàn cầu đã được hồi đáp chủ yếu bởi ngành công nghiệp hoá chất. Thuốc diệt cỏ có hiệu quả và đôi khi cần thiết, nhưng một số lại gây ra những vấn đề nghiêm trọng, đặc biệt nếu lạm dụng. Các hợp chất độc hại đe doạ động vật và sức khoẻ cộng đồng khi chúng tích tụ trong thực phẩm, nước ngầm và nước uống. Chúng cũng làm hại người sử dụng chúng.

Trong những năm gần đây, ngành công nghiệp hóa chất đã đưa ra một số chất diệt cỏ có vẻ sinh thái hơn. Tuy nhiên, các hóa chất mới không thể giải quyết được vấn đề cỏ dại trên thế giới. Do đó, các nhà khoa học đang khám phá năng lực diệt cỏ bẩm sinh của sinh vật sống, chủ yếu là côn trùng và vi sinh vật.

Các tác nhân sinh học hiện nay đang sử dụng rất thân thiện với môi trường và không gây hại cho con người. Chúng có thể được lựa chọn bởi khả năng tấn công các mục tiêu đã chọn của chúng và cây mùa vụ và các cây trồng khác không bị ảnh hưởng. Ngược lại, một số hóa chất có hiệu quả nhất giết chết hầu như tất cả các cây mà chúng tiếp xúc, chỉ còn lại những cây có khả năng đề kháng tự nhiên hoặc đã được biến đổi gen để đề kháng. Hơn nữa, một số tác nhân sinh học có thể được sử dụng một lần, sau đó không cần thiết điều trị nào nữa. Hóa chất thường phải được sử dụng nhiều lần trong mỗi mùa vụ.

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 37.  Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds – any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They...
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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 37.

  Humans have struggled against weeds since the beginnings of agriculture. Marring our gardens is one of the milder effects of weeds – any plants that thrive where they are unwanted. They clog waterways, destroy wildlife habitats, and impede farming. Their spread eliminates grazing areas and accounts for one-third of all crop loss. They compete for sunlight, nutrients, and water with useful plants.

The global need for weed control had been answered mainly by the chemical industry. Its herbicides are effective and sometimes necessary, but some pose serious problems, particularly if misused. Toxic compounds threaten animal and public health when they accumulate in food plants, groundwater, and drinking water. They also harm workers who apply them.

  In recent years, the chemical industry has introduced several herbicides that are more ecologically sound. Yet new chemicals alone cannot solve the world’s weed problems. Hence, scientists are exploring the innate weed-killing powers of living organisms, primarily insects and microorganisms.

The biological agents now in use are environmentally benign and are harmless to humans. They can be chosen for their ability to attack selected targets and leave crops and other plants untouched. In contrast, some of the most effective chemicals kill virtually all the plants they come in contact with, sparing only those that are naturally resistant or have been genetically modified for resistance. Furthermore, a number of biological agents can be administered only once, after which no added applications are needed. Chemicals typically must be used several times per growing season.

The word ‘clog’ in bold is closest in meaning to

A. drain

B. grow along

C. obstruct  

D. float on

1
11 tháng 10 2018

Đáp án C

 Từ ‘clog’ in đậm gần nghĩa nhất với

 A. cống                      

 B. phát triển dọc theo            

 C. cản trở                   

 D. nổi trên

 ‘clog’ = obstruct: cản trở, làm tắc nghẽn