必须依赖前文对enjoying my racquetball class的探讨才有效度。
三， 考核知识点：考查根据段落中的支持句（supporting sentences）来推断主题句（topic sentence）的能力。
●试题：
18. Read the following paragraph carefully and select the best topic sentence from the four possible answers that follow the paragraph.
Topic sentence：
First， there are always customers to be served. I work in a downtown McDonald‘s that gets lots of traffic， and as soon as I serve one customer， there is always another one ready to order. There is constant pressure because I can never step back for a few minutes and relax. Second， I have to put together all of the orders myself. To do that， I have to move all over the serving area： French fries on one side， drinks on the other， and burgers in middle. It’s easy to get sloppy and spill a Coke or throw French fries on the floor. Also， I must always move at a fast pace. McDonald‘s has an image to uphold， and its workers must scurry about like ants. If I don’t move fast enough， some customers will say， “Hey， speed it up，” or “I though McDonald‘s had fast service.” And with all of this nonstop work， I only get one ten-minute break every two hours. However， ten minutes isn’t enough time to rest and feel like getting back to work. It only gives me enough time to realize hoe tired I am， so I go back to work depressed. Finally， my manager really keeps the pressure on. He watches us like a hawk， and every time I do something wrong， he seems to catch it. He also has a reputation for firing people， and he never lets any of the workers feel that their jobs are safe. By the end of the day， I‘m emotionally and physically drained， like everyone else， and we all head out the door grumbling.
[A] The hamburger sold at McDonald‘s is my favorite food.
There are several reasons that I like McDonald‘s.
[C] Working at McDonald‘s is very tiring.
[D] I have no idea about working at McDonald‘s.
●答案：
18. Topic sentence： [C] Working at McDonald‘s is very tiring.
●解题关键：
（1） 明确主题句（topic sentence）与支持句（supporting sentence）的关系：主题句（topic sentence）是统领，起着开宗明义、提纲挈领的作用，其余的与主题相关的支持句（supporting sentences）都围绕主题句来展开，用来阐明、证实主题句。
（2） 18题段落中的各句描述了麦当劳员工工作的情况：店员要不停地接待一个又一个顾客，异常忙碌，身体极度疲劳，还要承受顾客的诸多抱怨和经理的严厉监督。所有这些supporting sentences都用细节支持说明一个事实：在麦当劳工作十分辛苦。故[C]句Working at McDonald‘s is very tiring就是该段落的topic sentence.
（3） [A]、、[D]三句，与段落各支持句内容或不相关或相矛盾，故为错解。
