be busy to do sth.和be busy doing的区别

e busy doing sth 其实也可以是 be busy (in) doing sth。意为忙于做某事。例：I'm busy (in) doing my home work。be busy to do sth。如果是 be too busy to do sth。那就是too。。。to。。。结构了,可以这样用,太忙了以至于不能干什么。但是如果没有那个too那就不能用to do只能用doing表示忙于做某事