LESSON ONE 1
LESSON TWO 7
LESSON THREE 13
LESSON FOUR 20
LESSON FIVE 25
LESSON SIX 31
TEST YOURSELF FOR LESSON 1—LESSON 6(Ⅰ) 38
TEST YOURSELF FOR LESSON 1—LESSON 6(Ⅱ) 46
LESSON SEVEN 57
LESSON EIGHT 64
LESSON NINE 71
LESSON TEN 80
LESSON ELEVEN 87
LESSON TWELVE 95
TEST YOURSELF FOR LESSON 7—LESSON 12(Ⅰ) 102
TEST YOURSELF FOR LESSON 7—LESSON 12(Ⅱ) 113
期终试题（Ⅰ） 121
期终试题（Ⅱ） 130
Key to the Exercises of Lesson One 140
Key to the Exercises of Lesson Two 141
Key to the Exercises of Lesson Three 142
Key to the Exercises of Lesson Four 143
Key to the Exercises of Lesson Five 144
Key to the Exercises of Lesson Six 145
Key to Test Yourself for L.1—L.6(Ⅰ) 146
Key to Test Yourself for L.1—L.6(Ⅱ) 147
Key to the Exercises of Lesson Seven 149
Key to the Exercises of Lesson Eight 150
Key to the Exercises of Lesson Nine 151
Key to the Exercises of Lesson Ten 152
Key to the Exercises of Lesson Eleven 153
Key to the Exercises of Lesson Twelve 154
Key to Test Yourself for L.7—L.12(Ⅰ) 155
Key to Test Yourself for L.7—L.12(Ⅱ) 157
期终试题（Ⅰ）答案 158
期终试题（Ⅱ）答案 159
编后 161