37. This is one of the means ______ the electric energy is conducted from one place to another.

A. by which 　　　　　 B. by that 　　　　　　　

C. through which 　　　 D. through that

36. In the dark street, there wasn’t a single person ______ she could turn for help.

A. that B. who C. from whom D. to whom

35. She heard a terrible noise, ______ brought her heart into her mouth.

A. it 　B. which 　C. this 　D. that

34. He paid the boy 10 dollars for washing ten windows, most of ______ had not been cleaned for years.

A. these B. those 　C. that 　D. which

33. All ______ is needed is a supply of oil.

A. the thing B. that 　C. what　 D. which

32. The buses,__were already full, were surrounded by an angry crowd.

A.most of them 　B. most of which

C. which most 　D. that most

31. ______ is natural, he married Mary.

A. It　　 B. What 　　C. Which　 D. As

30. His father died last year, ______ made it impossible for him to go abroad.

A. when 　B. which　 C. as 　D. that

29. He must be from Africa, ______ can be seen from his skin.

A. that 　　B. as 　　C. it 　　D. what

28. The reason ______ he didn’t come was __ he was injured.

A.that, because 　B. why, that 　　

C.why, because D. that, that