Yêu cầu chung
Question 21 - 30.
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the best answer to each of the questions.
(I) The cause of tooth decay is acid, which is produced by bacteria in the mouth. (II) 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. (III) To keep your teeth healthy, a regular dental hygiene program should be followed. (IV)
Removing plaque with a toothbrush and dental floss temporarily reduces the numbers of harmful bacteria in the mouth, thereby lowering the risk of tooth decay. This practice also makes the surfaces of the teeth more accessible, which enables 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, opt for foods with fiber, such as raw carrot sticks, apples, celery sticks, etc., that naturally scrape off plaque, acting as a toothbrush. Following these guidelines when consuming sweets and maintaining a thorough oral care routine can significantly reduce the risk of cavities and improve overall dental health.
(Adapted from https://www.verywellhealth.com/tooth-erosion)
The phrase "scrape off" can best be replaced by
take on
check in
wipe off
build up
Giải thích chi tiết
✅ Đáp án: wipe off
🔎 Lí do: ✔ “...foods with fiber, such as raw carrot sticks, apples, celery sticks, etc., that naturally scrape off plaque, acting as a toothbrush.”
Cụm “acting as a toothbrush” gợi rằng hành động “scrape off” giống như chuyển động chà xát của bàn chải đánh răng để loại bỏ mảng bám. → “scrape off” theo đó mang nghĩa loại bỏ bằng cách chà hoặc cọ mạnh trên bề mặt.
✔ Trong các lựa chọn, wipe off (lau, chùi sạch đi) thể hiện đúng nhất hành động làm sạch bề mặt — tương đương với việc bàn chải “chà sạch mảng bám.”
🚨 Những đáp án còn lại thì sao? ❌ take on: = đảm nhận, không mô tả hành động vật lý. ❌ check in: = đăng ký hoặc vào chỗ ở, không liên quan. ❌ build up: = tích tụ, hình thành mảng bám, mang nghĩa ngược lại với “scrape off.”
