第二部分知识运用 (共两节，满分20分)
第一节单项填空（共10小题；每小题1分，满分10分）
从A、B、C、D四个选项中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
21. When Li Lei was a small child, he hoped to be ______ policeman after he grew up and finally his dream came true.
A. a B. an C. the D. 不填
Thinking that you know _________ in fact you don’t is a serious mistake.
| A．what | B．that | C．when | D．however |
—Oh,life is so boring!
—Please don’t think so.I suppose you’ve come to the point _________ a change is needed.
| A．where | B．when | C．which | D．as |
__________ is announced in today’s paper,they have succeeded in solving many problems in accordance with the new theory.
| A．It | B．That | C．What | D．As |
This is an unpleasant subject __________ we might argue for a long while.
| A．in which | B．with them |
| C．about which | D．with it |
The sale usually takes place outside the house,with the audience __________ on benches,chairs or boxes.
| A．having seated | B．seating |
| C．seated | D．having been seated |