51. I am sure ____ you said is true.
A. what       B. that      C. which     D. who
52. The trouble is ____ we can not find such an expert.
A. why              B. that
C. where          D. /
53. It has not been decided ____ they will leave.
A. why              B. when
C. which             D. what
54. We shall go ____ you are ready.
A. while     B. as soon as      C. as       D. since
55. He will tell you about it ____ you get there.  A. while      B. as      C. when      D. /
56. Don't try to get off the bus ____ it has stopped.
A. while             B. as                C. since             D. before
57. I'll come and see you _____ I go to the countryside.
A. while             B. when          C. as soon as         D. before
58. ___ he came to study in the university, he has made much progress in the study of English.
A. While             B. When             C. Since             D. After
59. Things have changed a lot ____ I wrote to you last time.
A. when             B. since              C. as                D. before
60. I can't use your pen, ___ there is no ink in it.
A. for    B. when   C. if    D. whether 
61. I'd like to go swimming ____ the water is not too cold.
A. for               B. unless             C. if                D. whether
62. Difficulties are nothing ___ we are not afraid of them.
A. for               B. as                C. if                D. whether
63. The doctor will not perform the operation ___ it is absolutely necessary.
A. when             B. if                 C. for               D. unless
64. Go back ___ you came from.
A. until       B. where       C. which        D. when
65. He lay ___ the grass was the thickest.  
A. where     B. when    C. that       D. after
66. You will find friendly people ___ you go in China.
A. where             B. and               C. wherever          D. so
67. ___ it was already dark, they went on working in the fields.
A. If                B. Whether           C. But               D. Though
68. ___ he has finished writing the novel is unknown. 
A. If        B. Whether     C. When       D. While
69. We'll go and see the patient ___we are busy.  
A. even if       B. for          C. if          D. while
70. The museum is ___ far ____ it will take us half an hour to get there by bus.
A. such... that        B. as...as         C. so...that           D. so … as

答案：

1~5 ABCDA 6~10 CDACA 11~15 ACDBA 16~20 BCBAB
21~25 CDABC 26~30 BBABC 31~35 DACBC 36~40 AABCD
41~45 AAABC 46~50 DCDBC 51~55 ABBBC 56~60 DDCBA
61~65 CCDBA 66~70 CDBAC