I understand the gereneral idea of certainty/ probability involved in the choice of future "tense" structures in English. I've read the rules countless times, but there are still situations when I'm not sure which to pick. I've tried youtube videos with natives explaining it, however they contradict each other most of times. I have this intuition that seeing "will" as a modal verb could be helpful... Can anybody help me?
It's not about probability; I was surprised to see one source claim that it was. I've attached an image that explains it well imo, but could you give an example or two where it becomes difficult to choose?
(edit: I just realized that this chart sucks. They are interchangeable in each of these sentences, and only 3 have different nuances:
1) I will help you with it. = This could be an offer.
I'm going to help you with it. = This isn't an offer, and it's a pretty common mistake made by learners. It sounds more like you're stating a fact; maybe you want to assure your friend that you are keeping your promise to help them.
2) She won't listen to anything I say. = This could be either present or future.
She's not going to listen to anything I say. = This can only be future.
3) I think I'm going to throw up. = Said like this normally it means you have no control over it.
I think I will throw up. = Said like this it means you can decide whether to do it or not. This is also a pretty common mistake make by learners.
Regarding the "gonna" comment - you need to be careful with that one because it's not always possible. I think it only works when it's in front of a verb.
Ex: I'm going to eat can be said "I'm gonna eat".
But: I'm going to the movies CANNOT be said "I'm gonna the movies".
I'm reading the Malazan Book of the Fallen.
Thanks, leosmith! This explanation based on probability is really common in Brazil! "will" would be a less probable future than "going to". But I"ve always felt it wasn't enough, there are situations one can't decide based on that. I simply cannot think of any example when I need one!
What about the use of presente continuous with a future meaning? In here we explain like this: when the event is scheduled.