It remains a(n) question whether middle school children should be allowed to use mobile phones at school.
24.The policemen_______the stolen place again and again,and finally they found the evidence who stole the antique(古董).
23.What the boss really doubts is__________his employees will go on working in the company.
32. His composition won first prize, ______ made him too happy to sleep for nights.
31. We are waiting ______ for your absence.
30. With little knowledge about the area he succeeded ______ many researchers failed.