改正下列句子中的错误

1.The room which he worked in is now kept in a good state.

2.Parents should often ask their children that he or she has been doing and about any friends they make on-line.

3.He paid the boy 20 yuan for washing 10 windows,most of that hadn't been cleaned for at least a year.

4.My father has been working in that company for 20 yuan.

1.The room where he worked is now kept in a good state.
2.Parents should often ask their child what he or she has been doing and about any friends they make on-line.
4.My father has worked in that company for 20 years.