69. The old woman has loved Tom _____ he were her son.

A. because　 　　　　　 B. as　 　　　　　　　　　 C. if　 　　　　　　　　　　　　 D. as though

68. _____ I admit that the problems are difficult , I don’t agree that they cannot be solved.

A. While　 　　　　　　　 B. Suppose　 　 C. Because　 　　　　　　　 D. as though

67. They agreed to rent the house ______ the roof should be repaired.

A. on condition that　　　　 B. as soon as　 　　　 C. when　 　　　　　　 D. unless

66. ______ you understand this rule, you’ll have no further difficulty.

A. while　 　　　　　　　 B. Once　 　　　　　　 C. Though　 　　　　 D. Unless

65. Mother shut the window ______ she might keep the insects out.

A. because　 　　　　　 B. in order that　 C. till　 　　　　　　　　　　　　　 D. as

64. Anyone can borrow books from this library _______ he keeps them clean and returns them in time.

A. even if　 　　　　　　 B. unless　 　　　　　　 C. so that　 　　　　　　　　　 D. as long as

63. Doing your homework is a sure way to improve your test scores, and this is especially true______ it comes to the classroom tests.

A. before　 　　　　　　 B. as　 　　　　　　　　　 C. since 　　　　　　　 D. when

62. Just as the tree is the unit of a forest and the book the unit of a library, ______ the molecule is the unit of matter.

A. as　 　　　　　　　　　 B. like　 　　　　 C. so　 　　　　　　　　　　　　 D. thus

61.　　 You can arrive in Beijing earlier for the meeting __　 　you don’t mind taking the night　　 train.

A. provided　 　 B. unless　 　　　　　　 C. though　 　　　　　　　　　 D. until

60.　　 ______ nobody was very enthusiastic about it, they decided to cancel the trip.

A. See that　 　　　　　 B. Seeing that　 C. So 　　　　　　　　　　　　 D. When