有一些英语题麻烦作答

题目

有一些英语题麻烦作答
按要求改写句子
1I think he needs our help.（改为否定句）
2You should eat some vegetables.（改为否定句）
3You need to see a dentist.（改为一般疑问句）
4He stayed in Beijing two weeks ago.（改为一般疑问句）

答案

I don't think he needs our help.
You shouldn't eat any vegetables.
Do you need to see a dentist?
Did he stay in Beijing two weeks ago?