第一部分 阅读理解(共两节，满分40分)
第一节(共15小题；每小题2分，满分30分)
阅读下列短文，从每题所给的四个选项(A、B、C和D)中，选出最佳选项。
A
Dentists have found “striking” levels of bad teeth in athletes competing at the London 2012 Olympic Games.
A fifth of athletes surveyed said their oral health actually damaged their training and performance.
The study，published in the British Journal of Sports Medicine，suggested cavities(蛀牙)，tooth erosion and gum(牙龈)disease were common.
