21. Though he is in his sixties, ______ he works as hard as a young man

　　A. yet B. but C. and D. and yet

　　22. The two girls look ____ much alike ____ no one can tell them apart.

　　A. so, that B. so, and C. as, that D. such, that

　　23. John shut everybody out of the kitchen _________ he could prepare his grand surprise for the party.

　　A. which　　 B. when　　 C. so that　　 D. as if

　　24. Beijing is larger than ____ city in Africa

　　A. any B. other C. each D. any other

　　25. We must hurry up ________ catch the last train.

　　A. that B. so that to C. in order that D. in order to

　　26. No matter________ hard it may be，I will carry it out.

　　A. what B. whatever C. how D. however

　　27. ________ you may do，you must do it well.

　　A. Which B. Whenever C. Whatever D. When

　　28. --- Are you thinking about going to New York for the holiday?

　　--- No. But if I ________ the time，I would definitely go.

　　A. have B. h ad C. have had D. would have

　　29. ________ you are so weak，you’d better stay at home.

　　A. Since B. For C. Because D. Though

　　30. English and French are taught here. You can choose ________ you like.

　　A. no matter which B. whichever C. which D. whatever

　　31. I saw Mr. Smith last Sunday. We had not seen each other ________ I left London.

　　A. as B. before C. since D. till

　　32. I’ll be back before you ________.

　　A. will leave B. will have left C. leave D. would leave

　　33. The problem won’t be settled until we ________ a chance to discuss it thoroughly.

　　A. have had B. will have C. will have had D. would have

　　34. If you ________ this experiment，you will understand the theory better.

　　A. will be doing B. have done C. will have done D. would do

　　35. They went on working ________ it was late at night.

　　A. even if B. as if C. however D. as though

　　36. I hurried ________ I wouldn’t be late for class.

　　A. since B. so that C. as if D. unless

　　37. ________ you talk to someone or write a message，you show your skills to others.

　　A. At times B. Some time C. By the time D. Every time

　　38. Although he is considered a great writer，________.

　　A. however his works are not widely read B. but his works are not widely read

　　C. his works are not widely read D. still his works are not widely read

　　39. We should finish the important job，________.

　　A. long it takes however B. it takes however long

　　C. long however it takes D. however long it takes

　　40. ________ comes to the party will receive a gift.

　　A. No matter who B. Who C. Which one D. Whoever