30. Everyone in our class was working hard and doing what we could _______ a good college.

A. enterB. to enter

C. enteringD. entered

【解析】B。此句为省略句，即在 could 后省略了动词 do，若把句子补完整应为Everyone in our class was working hard and doing what we could do to enter a good college。即句中的不定式短语(to enter a good college)是用作目的状语的，而不是与情态动词(could)一起构成谓语。

31He ran as fast as he could _____ to catch the early bus.

A. to hope          B. hope             C. hoping          D. hoped

【解析】 C不是A，其中的现在分词短语 hoping to catch the early bus 用作伴随状语。

   29. You should ______ what your parents expect of you.

    A. live up to              B. stand up to      C. look up to              D. run up to

【解析】A.live up to 意为“实践，做到”；stand up to 意为“勇敢地抵抗”；look up to 意为“尊敬，仰望”；run up to 意为“达到，积累到”。

28. To my surprise， the manager ______ 30 dollars from my salary without any good reason.

    A. cut off                 B. held up         C. brought down            D. kept back

【解析】D.keep back 意为“扣下，留下，阻挡，隐瞒”；hold up意为“举起，支撑”；bring down 意为“打倒，击落，打死，降低”；cut off 意为“切断，断绝”。

27. The mother often tells her son to be a good boy， warning him to ______ trouble.

    A. hold back fromB. keep out of

    C. break away from D. get rid of

【解析】B.hold back from 意为“向……隐瞒”；keep out of 意为“使在……之外”；break away from 意为“脱离”；get rid of 意为“摆脱，消除，去掉”。

26. I can ______ some noise while I’m studying， but I can’t stand very loud noise.

    A. put up with          B. get rid of             C. have effect on          D. keep away from

【解析】A.put up with 意为“忍受，容忍”；get rid of 意为“摆脱，消除，去掉”；have effect on 意为“对……有影响”；keep away from意为“远离，不接近”。

25. John has put on so much weight recently that his mother has to ______ all his trousers to his measure.

    A. let out                 B. give away              C. bring in                D. make up

【解析】A.let out 意为“放掉，泄露，放大，出租”；give away 意为“送掉，分发，放弃，泄露， 出卖，让步”；bring in 意为“生产， 挣得，介绍引进”；make up 意为“弥补，虚构，缝制，整理，和解，编辑，化妆”。

24. The government has _______ the parents to work with teachers in the education of their children.

    A. asked for               B. called for             C. looked for       D. paid for

【解析】B.call for 意为“要求，提倡”；ask for 意为“请求，索要”；look for 意为“寻找”；pay for 意为“为……付钱”。

23. The plan    ___ just because people were unwilling to co-operate（合作）。

    A. broke down             B. pulled down         C. turned down           D. put down

  【解析】A.break down意为“中止，毁掉，压倒，停顿，倒塌”；pull down 意为“摧毁，推翻，使降低，使身体变差”；turn down 意为“拒绝，关小音量，减弱，降低”；put down 意为“放下，拒绝，镇压，削减，记下”。 

 22. My study of biology has ___C___ much of my spare time， but it has given me a great deal of enjoyment.

    A. taken off               B. taken down           C. taken up                D. taken away

【解析】C.take up 意为“开始（学习或从事等），继续，占去，接纳，提出”；take off意为“脱下，起飞，打折，请假”；take away 意为“取走”；take down 意为“写下，拆下”

21. Elephants would ______ if men were allowed to shoot as many as they wished.

    A. die down               B. die out          C. die away           D. die off

【解析】B.die away 指“（声音、风、光线等）渐息，渐弱”；die down 指“（慢慢）熄灭，平静下来”；die off 指“一个一个地死去”；die out 指“（家族、种族、习俗、观念等）灭绝，绝迹”。