单句改错⒈Having been ill for along time,so she fell behind her c

1.Having been ill for a long time,she fell behind her classmates.
"Having been……"是状语而不是一个句子,所以后面不需要so这个连词
2.They may go to London,but they were not sure.
be sure是一个固定短语
3.I don't think he can do de work well,can he?
I don't think这个句型要注意否定转移,也就是把don't的否定转移到can上,所以反意疑问句就要用can
4.The book which brought for me by my brother cost a lot.
cost就是花费的意思,后面就不用money了,感觉是个这样子,这道题不太肯定
5.You must do everything you can to help them.
to后面是目的状语,读句子时要在can后停顿
6.The farmers are very busy today and they won't stop working until dark.
这句话想要说的是：农民们非常忙,他们不天黑不停止工作
⒎After mixing the three ,he dipped one of his fingers into the cup.
mix就是混合的意思,似乎没有mix……together这种用法,还有fingers
⒏The old man asked a policeman ,could you show me how to get to the post office?
how to do sth.

1.so去掉
2.certaining→certain
3.can't→can
4.for→to
5.can和help中间加入to
6.好像没错
7.finger→fingers
8.how和get中间加入to