Well, I might give up trying to understand the difference between those verb tenses.
I know the differences between them
Be going to: Plans planned; Predictions that you can see, and you have facts for that;
Will - Choices decided at the moment of speaking; Predictions that is not certain;
The problem is: I don't understand when to use them (Eg. : Well, I decided I'm going to/ will study tommorow) and I don't know why someone used "going to" or "will" (even if the "rules" are already specific and "easy")
And sometimes, they are interchangeable. How can I say they are are interchangeable?
And besides, there are some people who actually don't know that this difference exists
Thanks in advance. I just don't want to torture for grammar, which, at first, appears "that easy"