Do you know when to leave tomorrow morning为什么要选to leave不选wil

Do you know when to leave tomorrow morning为什么要选to leave不选wil When are you going to leave?这个句子能改为 When wil you leave? Do you know when the train to leave?与Do you know the train w I don't know when to leave为什么when后面要加to. when are you to leave What are you going to do when you leave school?不加冠词 英语：when are you to leave for home 为什么不是do you呢? I don't know when to leave When do you want to leave for beijing的意思 关于Are you ready to leave?为什么不能说Do you ready to leave? When will you leave tomorrow? When ( ) you ( ) beijing? Tomorrow. A.do ;leave for B.were ;