23. Mary as well as her sisters ______ Chinese in China.

A. are studying　 　　　　 　　　　B. have studied　　

C. studies　　　 　　　 　　　　　　D. study

22. Scientists are convinced___　　 the positive effect of laughter ____　　 　physical and mental health.

A. of, at 　　　　　　　 　B. of, on　 　　C. on, at 　　　　D. by, on

21. Lisa would rather_______ at home than_______ to the cinema . 　　 A .　staying; going　　 　　　　　　B .　staying; go　　　

C .　to stay; to go　 　 　　　　　　D .　stay; go

20. The president spoke at the business meeting for nearly an hour without ______ his notes.

　　　 A. bringing up　　　　　　　 　　　　　 B. referring to　　　　

C. looking for　　　　 　　　　　 D. trying on

19. My father ______ my brother for driving but he wanted to pick ______ the knowledge of the computer during his spare time.

　　　 A. advised; up　　　　 　　　　　 B. persuaded; out　　

C. intended; up　　　　　　 　　　 D. intended; out

18. Only then ____________how much damage had been caused.

　　　 A. she realized 　　　　　　 　　　　B. she had realized

C. had she realized 　　　 　　　　D. did she realize

17. Try to spend your time just on the things you find ______.

　　　 A. worth doing 　　　　　　 　　　　B. worth being done　　　　

C. worthy to being done　　　　 　 D. worthy being done

16. The children do not know how to _______ themselves properly at the party.

　　　 A. act　　　　　　 B. do　　　　　　 C. behave　　　　　　　　　　 D. advance