future

[Must]

He's going to call on the phone (The future)
Is it ok?

[Tdol]

It's fine.

[salma]

He's going to call on the phone (The future)
Is it ok? yes

* will and be going to is used to express future time
jack will finish his work tomorrow
jack is going to finish his work tomorrow
*the present progressive may be used to express future time when the idea of the sentence concerns a planned event or definite intention
sam has already made his plans . he is leaving at noontomorrow
note : a verb such as rain is not used in the present progressive to indicate future time because rain is not a planned event

i wish you got it
bye

[Casiopea]

Nice addition, Salma. One addition note, "It's going to rain" is fine. 'going to' expresses what the speaker assumes might or will happen, like this,

I think it's going to rain tomorrow.

note : a verb such as rain is not used in the present progressive to indicate future time because rain is not a planned event.

All the best,