21. A good many houses _______ knocked down by the earthquake.

　　A. was B. were

　　C. is D. are

　　22. A good teacher must know how to _______ his ideas.

　　A. convey B. display

　　C. consult D. confront

　　23. A good teacher should not confront his pupils _______ too much information in one lesson.

　　A. by B. with

　　C. from D. about

　　24. A large part of human activity, particularly in relation to the environment, is _______ conditions or events.

　　A. in response to B. in favor of

　　C. in contrast to D. in excess of

　　25. A love marriage, however, does not necessarily _______ much sharing of interests and responsibilities.

　　A. take over B. result in

　　C. hold on D. keep to

　　26. A man escaped from the prison last night. It was a long time _______ the guards discovered what had happened.

　　A. before B. until

　　C. since D. when

　　27. A man has to make _______ for his old age by putting aside enough money to live on when old.

　　A. supply B. assurance

　　C. provision D. adjustment

　　28. A neat letter improves your chances of a favorable _______.

　　A. circumstance B. request

　　C. reception D. response

　　29. A new technique _______, the yields as a whole increased by 20 percent.

　　A. working out B. having worked out

　　C. having been worked out D. to have been worked out

　　30. A person who makes wise decisions has _______.

　　A. a good brain B. a good intention

　　C. good judgement D. good imagination