Choose the best anwser

9. The boy comes into the class silently and sit ………. without permission.
A. down B. out C. on D. up
10. This words is strange. You have to look ………. . the meaning of it.
A. into B. down C. forward D. up
11. Shy people often find it difficult to ……… group discussions.
A. take place B. take part in C. get on with D. get in touch with
12. They’ve …….. a research project to investigate the harmful effects of air pollution.
A. brought in B. taken on C. set up D. turned down