单句改错,每句有一处错误。
1、I found the book she lost three days before.
2、By the end of this year,the factory will produced 20000 tractors.
3、I studied English since I was ten.
4、We have been waiting for her for two hours by the time she came.
5、Is this the second time he breaks the world record in the field and truck events?
6、We didn't see him at the lecture yesterday.He mustn't attend it.
7、Xiao Li is so wet.She must fall into the lake.
8、He slipped into the room conen no one looked at him.