49. I wrote to my parents once a week,____ I was too busy with my teaching work.

A. it　 B. unless　 C. when　　 D. as

48.I wonder ____ we can solve this hard problem.

A. what else　 B. how else　 C. that　　 D. as if

47. Mr Smith is ______ a good teacher ______ we all respect.

　A. such；that B. such； as

　C. so；that D. so； as

46. Wang Ling was elected ______ all he is the tallest.

　A. because B. because of

　C. for D. as

45. - Was it under the tree ______ you were away talking to a friend？

　- Sure. But when I get back there， the bike was gone.

　A. that 　　B.where C. which D. while

44. 　He will tell you _____ he expects will win such a match.

　A. why 　B. whom 　C. which 　　D. who

43. 　We should do more such exercises in the future， I think， _____ those we did yesterday.

　A. as 　　B. like 　C. about 　　D. than

42. 　Was it _____ she heard with her ears really made her frightened？

　A： what； that 　　B. it； that

　C. that； which 　　　D. what； 不填

41. 　I have nothing to confess. ______ you want me to say？

　A. What is it that 　　　B. What it is what

C. How is it that 　　　D. How it is that

40. 　- ______ was it ______ they discovered the entrance to the underground palace？

　- Totally by chance.

　A. What； that 　　　B. How； that

　C. When； how 　　D. Where； that