Question

[Lê Quỳnh Anh]

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 35 to 42.

        The main cause of tooth decay is acid, which is produced by bacteria in the mouth. The acid removes minerals from tooth enamel, allowing tooth decay to begin; the saliva in your mouth encourages remineralization and neutralizes the acid. The rate at which bacteria in the mouth produce acid depends on the amount of plaque on the teeth, the composition of the microbial flora, and whether the bacteria of the plaque have been “primed” by frequent exposure to sugar. To keep your teeth healthy, a regular dental hygiene program should be followed.

        Removing plaque with a toothbrush and dental floss temporarily reduces the numbers of bacteria in the mouth and thus reduces tooth decay. It also makes the surfaces of the teeth more accessible, enabling saliva to neutralize acid and remineralize lesions. If fluoride is present in drinking water when teeth are forming, some fluoride is incorporated into the enamel of the teeth, making them more resistant to attack by acid. Fluoride toothpaste seems to act in another way, by promoting the remineralization of early carious lesions.

                   In addition to a regular dental hygiene program, a good way to keep your teeth healthy is to reduce your intake of sweet food. The least cavity-causing way to eat sweets is to have them with meals and not between. The number of times you eat sweets rather than the total amount determines how much harmful acid the bacteria in your saliva produce. But the amount of sweets influences the quality of your saliva. Avoid, if you can, sticky sweets that stay in your mouth a long time. Also try to brush and floss your teeth after eating sugary foods. Even rinsing your mouth with water is effective. Whenever possible, eat foods with fiber, such as raw carrot sticks, apples, celery sticks, etc., that scrape off plaque, acting as a toothbrush. Cavities can be greatly reduced if these rules are followed when eating sweets.

According to the passage, all of the following statements about plaque are true EXCEPT _________.

A. It consists of acid producing bacteria

B. It is not affected by eating sweets

C. It can be removed from teeth by brushing and flossing

D. It reduces the positive effect of saliva

Answer 1

[Dương Hoàn Anh]

Chọn đáp án B

Theo bài đọc, tất cả những điều sau đây đều đúng về cao răng NGOẠI TRỪ _________       

A. Nó có chứa các loại vi khuẩn tiết ra axit

B. Nó không bị ảnh hưởng bởi việc ăn đồ ngọt

C. Nó có thể được loại bỏ ra khỏi răng bằng việc đánh răng và dùng chỉ nha khoa

D. Nó giảm tác dụng tích cực của nước bọt

Dẫn chứng:

- The rate at which bacteria in the mouth produce acid depends on the amount of plaque on the teeth, the composition of the microbial flora, and whether the bacteria of the plaque have been “primed” by frequent exposure to sugar. (Tỉ lệ vi khuẩn trong miệng tiết ra axit phụ thuộc vào lượng cao răng, thành phần của hệ vi khuẩn, và vào việc vi khuẩn của cao răng có được “phát triển” bởi việc tiếp xúc thường xuyên với đường hay không.” => A đúng, B sai

- Removing plaque with a toothbrush and dental floss temporarily reduces the numbers of bacteria in the mouth and thus reduces tooth decay. It also makes the surfaces of the teeth more accessible, enabling saliva to neutralize acid and remineralize lesions. (Loại bỏ cao răng bằng việc đánh răng và dùng chỉ nha khoa tạm thời làm giảm số lượng vi khuẩn trong miệng và do đó giảm được sâu răng. Điều đó cũng làm cho bề mặt răng dễ tiếp cận hơn, cho phép nước bọt trung hòa axit và bù khoáng cho các tổn thương.)

=> C, D đúng.