21. After ______ series of unsuccessful attempts, he has finally passed______ driving test.
A. /;the B. a; the C. the; a D. /;a
22. Remember to ______ the pockets before you put those trousers in the washing machine.
A. get through B. pass through C. go through D. get along
23. To improve your spoken English, you’d better listen to the tape______.
A. generally B. fluently C. frequently D. gradually