Lesson One 1
Lesson Two 9
Lesson Three 17
Lesson Four 25
Lesson Five 33
Lesson Six 39
Lesson Seven 47
Lesson Eight 55
Lesson Nine 65
Lesson Ten 73
Lesson Eleven 83
Lesson Twelve 93
Lesson Thirteen 103
Lesson Fourteen 111
Lesson Fifteen 119
Lesson Sixteen 129
Lesson Seventeen 137
Lesson Eighteen 147
Lesson Nineteen 155
Lesson Twenty 163
Lesson Twenty-one 171
Lesson Twenty-two 179
Lesson Twenty-three 187
Lesson Twenty-four 195
参考答案 205