Be careful! That cup is going to fall.
Dave can’t come because he is going to see the dentist.
I’m tired. I will go to bed now.
I can’t believe it! He is going to win the race!
‘Why have you got all this food and drink?’ ‘We are going to have a party.’
Don’t worry. We will tidy the house after the party. We promise!
Обоснование: be going to употребляется для очевидного предсказания по ситуации и заранее запланированных действий, а will — для спонтанного решения, обещания или предсказания.