57.________ is the most useful invention?　　　　　　　　　　　　　　 　B

A. Do you think which of these　　 　 B. Which of these do you think

C. Which of these you think　　　 D. You think which of these

56.The reason________ she gave for not being present was _______the heavy snow prevented her coming.　　　　　　　　　　　　　　　　　　　　　 that, that

55.Father made a promise________ I passed the examination he would buy me a new dictionary. 　　　　　　　　　　　　　　　　　　　　　　　　　　　that if

54.________ we’ll go camping tomorrow depends on the weather.　　 Whether　

53.________we can’t get seems better than_______ we have.　　　 What；what　　　

52.The question he asked was________ the electrical equipment should be stored.

where　　

51.What a pity________ is_______ you didn’t arrive by daylight. 　　　it；that

50.-I believe____ you’ve done your best and ___things will improve.

-Thank you.　　　　　　　　　　　　　　　　　　　　　　 that；that

49.I know nothing about her except_______ she is from Canada. 　　　　　that

48.We know little about the young lady except_______ you told me. 　　　what