[Grammar] be about to do/ be going to do/ be to do/be doing/will do

[toutoublue]

Hello everyone,

I have been haunted by this question for a while: what are the differences between be about to do , be going to do, be to do, be doing and will do ? I guess there are some differences in time, though I am not sure at all.

Are there any differences between the following sentences?

I am about to leave.
I am going to leave.
I am to leave.
I am leaving.
I will leave.

Any answers would be appreciated.

 

[5jj]

Yes, there are differences, but what they are will depend on the context. You may find this helpful: Ways of Expressing the Future in English - Articles - UsingEnglish.com