开头段的两句话首先引入话题和给出结论：
How many teeth have you had filled in the past two years?If you follow the advice of Dr. Faustick you may be able to reduce the number of your visits to a dentist.
紧接着引出Dr. Faustick的对照试验：早晚刷牙组和每顿饭后刷牙组：
Dr. Faustick conducted a two-year survey to find out how to prevent or reduce dental decay. 946 students took part in an experiment. 523 students cleaned their teeth within ten minutes of eating when possible they used a toothbrush, when this was impossible they washed their mouth thoroughly with water. The remaining 423 students merely cleaned their teeth when they went to bed and when they got up in the morning.
给出对照试验的结果：每顿饭后刷牙组效果好于早晚刷牙组
All the students had their teeth X-rayed at the end of the first and second years. At the end of the first year, the night and morning group had three times as many decayed teeth as the clean after each meal group. At the end of the second year the latter group had 53 percent fewer decayed teeth than the former group.
研究者自己的切身经历的结果进一步来证实实验结果并给出原因分析是因为食物中的糖分是主要影响因子。
Dr. Faustick has cleaned his teeth after meal for thirteen years and has not had a single decayed tooth. He pointed out that sugar is a major agent in dental decay. Particularly the sugar in sweets, cakes, and soft drinks.
如何规避这种不好的结果呢？作者给出了理想情况和不切实际的情况的解决方案
Ideally you should keep a tooth brush in your pocket and use it immediately after you have finished eating. When this is impractical you can at least make sure that you have a drink of water and let the water through your teeth to force out any particles of food.
最后一小节，普遍性的大家的现状和坏牙的痛点和进一步突出了这样做的必要性。
Seven of out ten people loose at least half of their teeth by the time they are fifty. Many have a complete set of false teeth by that time. In any case neither toothache nor a visit to a dentist is very pleasant. So it is worthwhile making an effort to keep you own teeth as long as possible. The main preventative agent is simply water.
问题：
14. According to the passage what kind of food is most likely to cause dental decay?
A) Coca Cola
B) Sausage
C) Milk
D) Fried chicken
15. What does the passage tell us about the condition of Dr. Faustick's teeth?
A) He has had thirteen decayed teeth
B) He doesn't have a single decayed tooth
C) He has fewer decayed teeth than other people of his age
D) He never had a single tooth pulled out before he was fifty.
16. What does Dr. Faustick suggest to prevent dental decay?
A) He has had thirteen decayed teeth
B) He doesn't have a single decayed tooth
C) He has fewer decayed teeth than other people of his age
D) He never had a single tooth pulled out before he was fifty.
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