两者区别在于: be to do:有责任,义务,约定的含义,还被用作将来时态,计划做某事. e.g Parents are to take care of their children. be about to do:表即将做某事,无感情色彩. e.g The plane is about to take off. 楼下的抄袭呀.
be to do是指将要作,但没有说什么时候做; be about to do是指马上作,立即做。 两者区别在于: be to do:有责任,义务,约定的含义. e.g Parents are to take care of their children. be about to do:表即将做某事. e.g The plane is about to take off.