20. Didn’t it ever ________to you that one day you wouldn’t be fired because of your carelessness?

　　 A. dream　　　　 B. occur　　　　 C. strike　　　　 D. happen

19. In a sports team each player has a clear role, and there are few occasions ________members are confused or uncertain of their roles.

　 　　 A. why　　　　　　　 　B. where　　　　　　　　 C. when　　　　　　 　　 D .in which

18. If you are out to get up early and do exercises every morning, it will_____good health.

　 A. get across　　　　 　 B. end up in　　　　 C. make for　　 　 　D. contribute for

17. They _____ on the program for almost one week before I joined them, and now we _____ it as no good results have come out.

　 A. had been working; are still working

B. had worked; were still working

　 C. have been working; have worked

D. have worked; are still working