Page 223 - Practical English Usage 3ed - Michael Swan, Oxford

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subordinate clauses: when she gets a job
The simple present is often used with a future meaning in subordinate clauses - for example after what, where, when. until, if, than. For details. see 580.
I'll tell you what I find out. (NOT ••• WhfJt tlljil'lti6Itt.)
She'll pay us back when she gets a job. (NOT ••• when she'll get fJ job.) Alex will see us tomorrow ifhe has time. (NOT ••• ifhe ttJill Mve ",m.)
instructions: Where do I pay?
Occasionally the simple present is used with a future meaning when asking for and giving instructions.
Where do I pay? Well, what do we do now?
So when you get to London you go straight to Victoria Station, you meet up
with the others. Ramona gives you your ticket, and you catch the 17.15 train [or Dover. OK?
other cases
In other cases, we do not usually use the simple present to talk about the future.
Lucy's coming for a drink this evening. (NOT LItC}' oomes ...)
I promise I'll phone you this evening. (NOT .. pf'6tnise .. phone)'B1t thi3
evening.)
There's the doorbeLL - I'll go. (NOT •• •--f-gfr.)
future {6}: present forms or will?
Will is the 'basic' structure for talking about the future. We use will if there is
not a good reason for using present forms.
present reality
We prefer present forms (present progressive or going to ...) when we are talking about future events that have some present reality (see 213-214). In other cases we use will. Compare:
- I'm seeingJanet on Tuesday. (The arrangement exists now.)
I wonder ifshe'll recognise me. (not talking about the present) - We're going to get a new car. (The decision already exists.)
I hope it will be better than the last one. (not talking about the present) predictions: thinking and guessing about the future
In predictions, we use going to when we have outside evidence for what we say - for example black clouds in the sky, a person who is obviously about to fall.
See those clouds? It's going to rain. (NOT See tn63e elBtttis? It will ffJin.) Look - that kid's going to fall offhis bike. (NOT wok! ThfJt kiti'll/tlll tJjfhi3
bike.)
We prefer will for predictions when there is not such obvious outside evidence - when we are talking more about what is inside our heads: what we know, or believe, or have calculated. (When we use will, we are not showing the listener something; we are asking him or her to believe something.) Compare: ~
future (6): present forms or will? 216
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