目录 1
Unit 13 1
Exercise 1 1
Exercise 2 3
Exercise 3 5
Exercise 4 7
Unit 14 12
Exercise 1 12
Exercise 2 14
Exercise 3 15
Exercise 4 17
Unit 15 22
Exercise 1 22
Exercise 2 23
Exercise 3 25
Exercise 4 27
Unit 16 32
Exercise 1 32
Exercise 2 34
Exercise 3 36
Exercise 4 38
Unit 17 44
Exercise 1 44
Exercise 2 46
Exercise 3 47
Exercise 4 49
Exercise 1 55
Unit 18 55
Exercise 2 57
Exercise 3 59
Exercise 4 61
Unit 19 66
Exercise 1 66
Exercise 2 68
Exercise 3 70
Exercise 4 71
Unit 20 77
Exercise 1 77
Exercise 2 79
Exercise 3 81
Exercise 4 83
Unit 21 89
Exercise 1 89
Exercise 2 91
Exercise 3 93
Exercise 4 94
Unit 22 100
Exercise 1 100
Exercise 2 102
Exercise 3 104
Exercise 4 105
期末模拟试卷（一） 111
期末模拟试卷（二） 118
参考答案 124