A. who B. whom C. how D. which

　　2.That is ______ we differ.

　　A. that B. where C. what D. whether

　　3.Another worry is that telecommunication systems may isolate people ______ each other.

　　A. from B. for C. with D. to

　　4.If I ______ in your place， I wouldn‘t trouble him.

　　A. were B. had been C. could be D. was to be

　　5._______ the moon moves round the earth is well known to all of us.

　　A. That B. What C. When D. As

　　参考答案：

　　1.正确答案：B答案解析：with用于与make contact搭配。本题使用的短语是make contact with sb.whom在本句中引导的句子做介词with的宾语。由于位于介词后面，所以用宾格形式whom.

　　2.正确答案：B答案解析：where在本句中引导表语从句。句意：这就是我们的不同之所在。

　　3.正确答案：A答案解析：isolate sb/sth from sb/sth是固定搭配。

　　4.正确答案：A答案解析：本句是对现在的虚拟，所以条件状语从句用过去时。同时在虚拟语气中，一般不用was而一律用were，所以答案是A.

　　5.正确答案：A答案解析：本题的考点是：That引导的主语从句，注意that引导的主语从句在句中只起到连接作用，没有意义，也不做任何成分。