51. The investigation， _____ will soon be published， was made by John.

A. at which the results B. the results on which

C. whose results D. at whose results

52. Crude oil is refined in a refinery， _____ makes it possible to get many grades of oils for different uses.

A. as B. that

C. this D. which

53. I am sure that _____ you said is wrong.

A. which B. all

C. this D. how

54. He arrived late for the tea party， _____ made us all very disappointed.

A. which B. this

C. it D. that

55. The people at the party were worried about John because no one was aware _____ he had gone.

A. where that B. where

C. of the place where D. the place

56. Is there anyone you can think of _____ may know her address？

A. which B. that

C. who D. what

57. Perhaps the day will come _____ people will live 150 years.

A. which B. that

C. who D. what

58. It was raining， _____ was a pity.

A. what B. that

C. as D. which

59. This is the reason _____ an aeroplane can‘t fly in space.

A. which B. why

C. where D. for that

60. We‘ve tested three hundred types of boot， _____ completely waterproof.

A. no of which B. none of which

C. some of that D. neither of which