30、______some English-learning websites if you are free, and you will learn a lot about how to study English.

A. Having visited              B. To visit                  C. Visit                      D. Visiting

29、If we know about what causes endangerment, we may be able to takes measures______ it is too late.

A. until                  B. unless                      C. when                       D. before

28、

Our school ______the students to collect used batteries, ______a better environment.

A. appealed; in the hope of                     B. appealed; in the hope that

C. appealed to ; in the hope of                D. appealed to; in the hope that

27、Hardly ______their supper when the power was cut off.

A. he finished                                               B. he had finished

C. did he finish                                             D. had he finished

26、I look on it as a good opportunity to _________ fresh skills and broaden my knowledge.

A. acquire          B. require                 C. accept            D. receive

25、―May I use your cellphone?

―Sorry. It’s out of order and it ______.

A. is repaired                                                B. is under repairing

C. has been repaired                                      D. is being repaired

24、―What should I do now?

―I’d prefer ______if you didn’t smoke in front of children.

A. one                          B. that                          C. it                             D. this

23、I think we paid too much for the house, ______ that we needed to get the roof repaired.

A. considered        B. considering               C. if considered             D. to consider

22、― I’m bored. I have almost wasted the whole afternoon on it.  

― _______

A. Don’t mention it.  

B. I would leave that question alone if I were you.  

C. You always have no patience.  

D. Leave me alone. I’m bored too.

21、The teacher insisted _______ until we finished the work.  

A. we not rest             B. on our resting

C. we rested               D. we would not rest