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

20、There was something wrong with our car, so we had to go _______ on foot to the village.

    A. all the way                          B. at all times 

    C. all the places                       D. all the roads