Unit One 1
Unit Two 13
Unit Three 26
Unit Four 37
Unit Five 48
Unit Six 60
Unit Seven 72
Unit Eight 83
Unit Nine 94
Unit Ten 105
Unit Eleven 116
Unit Twelve 127
第一学期期末试题 138
Unit Thirteen 156
Unit Fourteen 167
Unit Fifteen 178
Unit Sixteen 190
Unit Seventeen 201
Unit Eighteen 212
Unit Nineteen 224
Unit Twenty 236
Unit Twenty-one 248
Unit Twenty-two 259
Unit Twenty-three 271
Unit Twenty-four 281
第二学期期末试题 292
练习检测题答案及解析 307