1、Politics ______ the art or science of government.

　　A. is　　B. are　　C. be　　D. being

　　2、My friend was very unhappy for not ______ to the concert.

　　A. to be invited　　B. have been invited

　　C. to have been invited　　　　D. inviting

　　3、The noise was caused by a dog ______ a cat through the garden.

　　A. chasing　　B. fighting　　C. running　　D. following

　　4、I must get up earlier tomorrow morning ______ late again.

　　A. not to be　　B. not being

　　C. so as not to be　　D. for not being

　　5、Because of her peculiar characteristics, she has a lot of difficulty ______ friends with her classmates.

　　A. to make　　B. making　　C. of making　　D. for her to make

　　参考答案&解析：

　　1、A　某些学科名称，虽然形式上是复数的，但谓语动词仍用单数，据此可将B排除。C 和D 语法上不通。A 为正确选择。

　　2、C　不定式被动语态否定式表达方式。由于主句是过去时态，音乐会已经开过，所以应该选择C。

　　3、A　现在分词短语表示伴随状况。本题的其他选项意思有误。

　　4、C　不定式用作目的状语。

　　5、B　have difficulty (in) + 动词 + -ing 是习惯用法，故选项A、C、D 均可排除。