Page 218 - Practical English Usage 3ed - Michael Swan, Oxford

211 future (1): introduction
There are several ways to use verbs to talk about the future in English. This is a complicated area of grammar: the differences between the meanings and uses of the different structures are not easy to analyse and describe clearly. In many, but not all situations, two or more structures are possible with similar meanings.
1 wilVshall
When we are simply giving information about the future, or talking about possible future events which are not already decided or obviously on the way, we usually use wiU (or Uweshall) + infinitive. This is the most common way of talking about the future. For details, see 212.
Nobody will ever know what happened to her.
f think Liverpool will win. I shall probably be home late tonight. Will and shall are also used to express our intentions and attitudes towards other people: they are common in offers, requests, threats, promises and announcements of decisions. For details, see 217.
ShaU I carry your bag? I'll hit you ifyou do that again. I'll phone you tonight.
Youcanhaveitforhalfprice.- OK.I'llbuyit.
2 present forms: I'm leaving; I'm going to leave
When we talk about future events which have some present reality - which have already been planned or decided, or which we can see are on the way - we often use present forms. The present progressive is common. For details, see 214.
I'm seeing John tomorrow. What are you doing this evening?
The present progressive ofgo (be going to ...) is often used as an auxiliary verb to talk about the future. For details, see 213.
Sandra is going to have another baby.
When are you going to get a job?
These present forms are especially common in speech (because conversation is often about future events which are already planned, or which we can see are on the way).
3 simple present: the train leaves ...
The simple present can also be used to talk about the future, but only in certain situations. For details, see 215.
The train leaves at halfpast six tomorrow morning.
4 other ways of talking about the future
We can use the future perfect to say that something will be completed, finished or achieved by a certain time. For details, see 219.
By next Christmas we'll have been here for eight years.
The future progressive can be used to say that something will be in progress at a particular time. For details, and other uses of this tense, see 220.
This time tomorrow I'll be lying on the beach.
future (1): introduction 211
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