第二部分 英语知识运用(共两节，满分45分)
第一节 单项填空(共15小题；每小题1分，满分15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。
21．________ guard whom we thought irresponsible was fired，because he fell asleep when he was on ________ guard.
A．A；a B．The；a
C．The；/ D．A；/
22．The key ________ the problem of traffic jams is to pay the “congestion charge” ________ by the mayor of London.
A．to solving；introducing
B．to solve；introducing
C．to solving；introduced
D．to solve；introduced
23．In this state，all the adults who ________ laws were to be severely punished.
A．went for B．stood for
