本讲为2006年下半年新的教学内容，请对照教材，练习册和语法书听录音！

Doing being done
Having done having been done
Done

To do to be done
To be doing
To have done to have been done
Having finished his homework, he went to bed.
Finished, the homework was put aside.
The book being written by him is what I need.
The book written by him is what I need.

Unit 6
Text A

重点词语
increasingly adv. 不断增加地
Their argument became increasingly bitter.

prevalent a. 流行的，普通的
These diseases are more prevalent among young children.

frame n. 构架，框架
The bicycle frame was chained to a post, so the thieves could only steal the wheels.