Hello, I try!
We use I'll when we decide to do something at the time of speaking:
Oh, I've left the door open. I?ll go and shut it.
What would you like to drink? I'll have an orange juice, please
You cannot use the present simple (I do/ I go etc.) in these sentences:
I'll go and shut the door (not "I go and shut")
We often use I think I'll... and I don't think I'll...
I feel a bit hungry. I think I'll have something to eat.
In spoken English the negative of will is usually won't (= will not):
I can see you're busy, so I won't stay long.
Do not use will to talk about what you have alresdy decided or arranged to do:
I'm going on holiday next Saturday. (not I'll go)
We often use will in these situations:
Offering to do something
That bag looks heavy. I'll help you with it (not "I help")
Agreeing to do something
A:You know that book I lent you. Can I have it back if you've finished with it?
B:Of course. I'll give it to you this afternoon (not "I give")
Promising to do something
Thanks for lending me the money. I'll pay you back on Friday (not "I pay")
Asking somebody to do something (Will you...?)
Will you please be quiet? I'm trying to concentrate.
Shall I...? Shall we....?
Shall is udes mostly in the questions.
We use shall I....?/ shall we....? to ask somedody's opinion (especially in offers or suggestions):
Shall I open the window? (=do you want me to open the window)
I've got no money. What shall I do? (=what do you suggest?)
Shall we go? Just a minute. I'm not ready yet
Where shall we go this evening?
Compare Shall I...? and will you...?
Shall I shut the door? (= do you wnat me to shut it?)
Will you shut the door? (=I want you to shut it)
Mi granito de arena!!!