对比结构常把两种对立的事物或同一事物的两个不同方面并列出来加以比较或对比。高考完形填空题常常利用句子之间的对比关系或者同一个句子的不同部分之间的对比关系设计题目。如：
A pupil who can do his homework in a quiet and___59___room is in a much better position than a pupil who does his homework in a small, noisy room with the television on.
59. A. furnished B. expensive C. comfortable D. suitable
【分析】本题利用相似短语之间的对比关系来命题。设空部分与下文的a small, noisy room with the television on存在对比关系。作者想借此说明“相同的作业”对于“不同家庭背景的学生”所表现出的事实上的不公平。答案为C。
If he did not know them, he would greet them with a few words about the weather, ___15___ he did, he would ask about their families or make ___16___, always cutting his cloth ___17___ his customers.
15. A. and then B. and so C. even if D. but if
【解析】本题考查了相似句型的对比关系。空格处要填的部分与前部分if he did not know them形成对比，这句话的大意是说：如果店主认识那些顾客了，就会询问他们的家庭或是开些玩笑。
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