11. Most of my students are ___________ to finish their homework on time. A. enough hard-working B. hard-working enough C. so hard-working D. very hard-working 12. Please turn __________ the lights before leaving the room. A. on B. off C. up D. down 13. We are trying to do a lot of things to keep the environment______________. A. pollution B. polluted C. unpolluted D. pollutant 14. Mrs Robison ______________ as a secretary in that company two years ago. A. worked B. has worked C. works D. is working 15. Her daughter rarely comes back home ______________ midnight. A. on B. in C. at D. of Part III. Each of the following sentences has one mistake. Identify the mistake by circling A, B, C or D . 16. Your new teacher has a round face, hasn’t she? A B C D 17.Betty is devoted to look after handicapped people . A B C D 18.We started cooking for the party four hours before. A B C D 19.I wish my parents will come back tomorrow . A B C D 20. The girl drove so careless that she had an accident. A B C D