to be doing 和 doing的区别

to be doing 和 doing的区别 be doing和doing的用法区别 be said to be doing和be said to have been doing的区别 be going to be doing和will be doing表示的是什么意思? 用 be doing 和be doing to do 造句 三个 be doing和be going to的区别和用法!be doing和be going to的区别和用法 be easy to do和 be easy doing 的区别 be to do和be doing的区别 be gonging to do和be doing的区别 be careful doing和be careful to do的区别? get used to doing和be used to doing的区别 关于devote的一个问题devote to doing和be devoted to doing有什么区别? be busy doing 和 be busy in doing 的区别? need+to be done和need +doing的区别 happen to do和happen to be doing 的区别?顺便分别解释下.我问的是happen to be doing 不是happen to doing~ be close to doing. be reduced to doing happen to be doing