27._________ computer games, his parents were very worried about his study.

　 　 A. Addicted to　 　　　　　　　　　 B .He addicted to　　

C. His addicting to　　 　　　　　　 D. Addicting to

28. The train had left, so we could do nothing but ________ another.

A. wait　 　　　 B. to wait　 　　　　　　 C. waited　 　　　　 D. waiting

29. This disaster ______ that people had no knowledge of first aid and they hadn’t known how to protect them-selves in face of danger.

　A. led to 　　　 B. contributed to 　 C. resulted in　 　　　 D. lay in

30. The boy wanted to play games at home but his mother told him __________.

A. not to　 　　 B. not to do　 　　 C. not do it　 　　 D. don’t do