基础英语 下PDF电子书下载

Unit4 1

Lesson Sixteen 1

Lesson Seventeen 15

Lesson Eighteen 31

Lesson Nineteen 45

Lesson Twenty 64

Unit5 78

Lesson Twenty-One 78

Lesson Twenty-Two 94

Lesson Twenty-Three 110

Lesson Twenty-Four 127

Lesson Twenty-Five 145

Unit6 158

Lesson Twenty-Six 158

Lesson Twenty-Seven 177

Lesson Twenty-Eight 193

Lesson Twenty-Nine 210

Lesson Thirty 231