21. ---You've dropped _____ “s‟‟ in the word “acros‟‟

　　---Oh, ____ letter “s‟ should be doubled like this “across‟. A. a, a

　　B. an, a

　　C. a, the

　　D. an, the

　　解析：本题考查冠词的用法。表示泛指时用不定冠词，a 用在辅音发音字母之前，an用在元音发音字母之前。s的读音为/es/,为元音发音。应用“an”,后面表特指，上面出现的，应用"the",答案为D.

　　22. ---The pen writes well though it doesn't cost much.

　　--- Let me have a try. So _____.

　　A. it is

　　B. it does

　　C. does it

　　D. is it

　　解析：同第7题，根据题意是表示同意对方的看法，而write要用do/does替代，pen为单数，所以答案是B。

　　23. ---The smell in the room is really terrible.

　　---You said it. Let's keep all the windows _____ .

　　A. closed

　　B. open

　　C. opening

　　D. to open

　　解析：keep+宾语+形容词 "使...保持某状态" keep+宾语+动词ing形式，也表示“使...保持某状态”但是宾语是后面动词的发出者，如:keep you waiting ,根据题意，房间里味道不好，要把窗户打开，而不是关上。答案是B。

　　24. ---____ the Internet _____ in your school?

　　---Yes, but the computer in our office has often broken down.

　　A. Is, used

　　B. Is, using

　　C. Does, use

　　D. Has, used

　　解析：根据句意，internet是被使用，应该用被动语态。答案为A。

　　25. ---Do you often get on-line?

　　---Yes. I ______ most of my time on it. It's a good way to kill time.

　　A. cost

　　B. spend

　　C. pay

　　D. take

　　解析：cost 一般物作主语，“花费” spend "花费时间或金钱" pay 支付(钱) take一般指花费时间。答案为B。

　　26. ---Did Tom’s parents go to the meeting yesterday?

　　---Yes, ____ of them did, but ____ spoke.

　　A. each, none

　　B. both, none

　　C. neither, both

　　D. both, neither

　　解析：根据题目意思，是父母两个人去了会议，后面有个but，表示转折，应该是都没有发言，答案为D。Both 两者都，neither两者都没有。

　　27. ---I eat ____ vegetables and ___ meat than I did last year.

　　---That's why you're getting fatter.

　　A. fewer, more

　　B. more, less

　　C. least, more

　　D. many, much

　　解析：第二句话的意思是：这就是你越来越胖的原因。那么可以判断第一句话是跟去年相比，我吃更少的蔬菜，更多的肉。而蔬菜是复数，只能用fewer来修饰表示比较少。less修饰不可数名词表示比较少。more是many 和much的比较级，可以修饰可数和不可数名词。答案为A。

　　28. ---_____ is the population of the town?

　　---Over 20,000 .And a third of the population ____ workers of the car factory.

　　A. What, are

　　B. How many, are

　　C. What, is

　　D. How many, is

　　解析：对人口提问用how large 或what . The population of ....作主语时谓语动词用单数。当主语表示人口的百分之几，几分之几时，谓语动词用复数形式。答案为A。

　　29. ---I tried to make Kate ____ her mind, but I found it hard.

　　---Well, I saw you_______ that when I went past.

　　A. change, do

　　B. changes, doing

　　C. to change, do

　　D. change , doing

　　解析：make是使役动词，后面接不带to的不定式作宾补。表示“让某人做某事”。see是感官动词，接现在分词做宾补，强调动作正在进行。本题的意思是：------我试图让凯特改变她的想法，但是我发现很难。-------是的，我经过时看见你正在劝她。答案是D。

　　30. ---Sorry，I am late.

　　---It doesn’t matter. The meeting ___ for just several minutes

　　A. has begun

　　B. has started

　　C. has been on

　　D. had been on

　　解析：begin,start是瞬间动词，不能与表示一段时间的状语一起用在完成时中。而根据题目可看出，是现在时，所以不能用过去完成时。答案为C。