This is the form that most people immediately associate with the future tense, but it is in fact restricted in its use. It has two main functions.
- the first is to talk about unplanned or spontaneous future events;
- the second is for predictions that are not based on current evidence.
Some examples should help to clarify the different meanings:
(The telephone rings) I'll get it.
I'll make us a cup of coffee.
In these two cases the speaker is deciding what to do on the moment without prior consideration. You may have noticed that they act as offers. This is also true of promises or threats like:
I'll give you the money back next week.
I'll kill you!
For predictions, we may hear or read sentences like:
I think it'll rain tomorrow.
There's no way that we will lose the game.
You will meet a tall, dark, handsome stranger.
There are two main functions of this tense; the first is to refer to premeditated intentions.
Examples of this are:
I'm going to take a few days off.
We're going to visit my parents at the weekend.
The meaning that the speakers want to get across here is that I/we hope that these events will take place, but they are always subject to change if needs be or if some unforeseen obstacle arises. There is a sense of an arrangement, but it has a rather indefinite feel to it.
The second use of this form is for talking about predictions based on present or past evidence. You may remember we said that will is used for referring to predictions that are not reliant on current evidence - going to, on the other hand, is used for those predictions where we can rely on present evidence or past experience. For example:
Look at those clouds - it's going to rain.
Have you heard that Jenny's going to have a baby?
Getting up at 4:00 in the morning is going to be a problem.
In the first sentence there is clear, visible evidence that my prediction is likely to come true. It would be, at best, unusual to use any other of the future forms in this situation and, at worst, incorrect. The prediction in the second example is based on information that I have heard directly from Jenny herself or from someone who already had the information. The final sense seems to be based on my past experience of getting up early in the morning.
While the going to future form is often used to discuss intentions (possibly prearranged), the Present Continuous is used more for referring to solid arrangements and plans. For example, we are more likely to prefer this form when we have made a booking at a restaurant or theatre or have bought tickets for a train/plane journey. This tense is often accompanied by a time adverbial such as next month, in July etc.
Next holiday we're staying in a five-star hotel. (the reservation has been made)
They're all taking the day off on the 7th.
I'm spending Christmas in the Bahamas.
The present simple tense is usually used to refer to future events that are scheduled (and outside of our control).
Hurry up! The train departs in 10 minutes.
I leave Frankfurt at 5 o'clock in the morning and arrive in New York at midnight the next day.
She has an appointment with the headmaster after school today.
There's no need to hurry. The train doesn't leave for another 30 minutes.
When does the meeting begin?