解析　句意：我们努力说服他停止上网，但是他不听。try to persuade努力说服，不一定听从；persuade说服；suggest建议，后常接动名词；demand要求。

21.I bought a dress for only 10 dollars in a sale; it was a real ________.

A.exchange B.bargain

C.trade D.business

答案　B

解析　句意：在特卖中我只花了10美元就买了一套裙子，真划算。exchange"互换"；bargain"便宜货，廉价货"；trade"贸易"；business"生意"。

22.With________little schooling，he couldn't teach________little children.

A.such；so B.so；such

C.such；such D.so；so

答案　B

解析　句意：他学问很少，不能教这么小的孩子。当名词前有表示数量多少的词修饰时，只能与so搭配。而little children表示小孩子，此时little相当于small。

23.________ nearly all our money，we couldn't afford to stay at a hotel.

A.Having spent B.To spend

C.Spent D.To have spent

答案　A

解析　句意：我们几乎已经花完了所有的钱，没钱住旅馆了。we与spend之间为主动关系，且spend这一动作发生在afford之前，故应该用现在分词的完成式。

24.How can I________to you people how important this is?

A.get it around B.get it down

C.get it together D.get it across

答案　D

解析　句意：我要怎么做才能让你们这些人理解这件事情的重要性？get sth across使理解......，把......表达清楚；get around四处走动；get down写下，记下；get together聚集。

25.Last summer I took a course on________poisonous gases.

A.how to deal with B.what to deal with

C.how to be dealt with D.what to be dealt with