第一部分、阅读理解（75分）
下面有三篇短文，每篇短文后有几个问题，每个问题都有四个备选答案。请仔细阅读短文，并根据短文回答其后面的问题，从四个备选答案中选择一个最佳答案涂在答题卡相应的位置上。
Choosing a Topic for Research
Because you are going to put a lot of time and energy into your research project(项目)，the topic is especially important. In many instances your instructor may give a specific (特殊的)topic. If this is done, you have little choice, but most instructors will permit or even welcome a slightly changed focus (中心)in a topic if it is supported by good thinking.