We continue with the topic will+ infinitive vs to be going to+ infinitive, but this time from a different perspective—future happenings and situations (predicting the future)
Sometimes there is not much difference between will and going to.
For example:
I think the weather will be nice this afternoon.
I think the weather is going to be nice this afternoon.
When we say something is going to happen, we think this is because of the situation now
For example:
Look at those black clouds. It's going to rain. (It will rain)
(We can see that it is going to rain from the clouds that are in the sky now.)
I feel terrible. I think I'm going to be sick. ( I think I'll be sick)
( I think I'm going to be sick because I feel terrible now.)
Do not use will in this type of situations
In other situations, use will:
Tom will probably get here about 8 o'clock.
I think Sarah will like the present we bought for her.
These shoes are very well made. They'll last a long time.