A
Peter knows that he (will / is going to) fly to Chicago next week.
Peter knows that he is going to fly to Chicago next week. - Use the future with "going to" to express future plans.
Oh no! I've broken the vase. What (am I going to say / will I say)?
Oh no! I've broken the vase. What will I say? - Use the future with "will" when reacting to something that happens at the time of speaking.
(The phone rings)
Julie: I (am going to/will) get it!
I'm going to get it' is very strange, because it makes us think that Julie knew the phone was going to ring before it did
Look at those clouds! It (is going to rain / will rain)!
Look at those clouds! It is going to rain! - Use the future with "going to" when you can see that something is about to happen.
John hasn't eaten. - Don't worry (I will make / I am going to make) him a sandwich.
John hasn't eaten. - Don't worry I will make him a sandwich. - Use the future with '"will" to react to a present situation.
I think the Conservatives (will / are going to) win the next election.
I think the Conservatives will win the next election.
A prediction based on opinion
Unless he arrives soon, we (will not go/are not going) to the party.
Unless he arrives soon, we will not go to the party. - Use the future with "will" in real conditional (first conditional) sentences.
I (am going to/will) help you tomorrow, if you like.
I'll help you tomorrow, if you like. = For promises / requests / refusals / offers
I'm sure you (will / are going to) love learning English at "Nazario English School". It has great tutors!
I'm sure you will love learning English at Nazario English School. It has great tutors!
Use will to talk facts or things that we believe are true.
The sun (is going to / will) rise tomorrow.
The sun will rise tomorrow = A future fact.
We (will / are going to) get married next year.
We are going to get married next year. = Planned action
I think you (are going to / will ) like this movie.
I think you will like this movie. = Prediction
"Where are you going on holiday?" I don't know yet, maybe (I am going to / I will) go to India.
Where are you going on holiday?" I don't know yet, maybe I will go to India. = A belief
You (are going to see / will see) Mr Thompson tomorrow at 10.00.
You are going to see Mr Thompson tomorrow at 10.00. = Planned action
This exercise looks really hard – I (am going to / will) help you.
This exercise looks really hard – I will help you. = Promise