第一部分：阅读理解（共2节，共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、D）中，选出最佳选项，并在答题卡上将该项涂黑。
A
YOU may like chewing gum (口香糖) after meals to stop your breath smelling bad; or your mother might use a special neutralizer (调理剂) to protect her permed hair (烫发). But have you thought about the chemical principles behind such everyday actions?
