They have done all they could "to help" him.为什么是"to help"?

They have done all they could "to help" him.为什么是"to help"? He invited all his neighbours to come over and help him.They They have go to help her和They have come to help her. they could have come to your help,but they_____in a traffic They decide to help him with his homework problem翻译 I have n they all believe it is in great help to students They are to help others. 英语问题：是They can help you to be relaxing还是They can help you to They do what they can to help others.为什么不是They do what they Some parents think that they have to help their children --- they have to help her do homework 同意句 They come to ask him for help when they are in danger.