conditionals: true, real and unreal
always true (zero conditional)
il X happens, Y happens
These sentences describe what always happens in certain circumstances eg scientific facts.
present simple present simple
When / Jf you press the switch, the light comes on.
real conditions (conditional 1)
if X happens, Y will happen
These sentencesdescribe what the speaker thinks will possibly happen as a consequence of a real situatior
present simple will future
Jf we do not deal with the global warming problem, temperatures will rise.
If we leave now, we'lI catch the bus. If we don't leave now, we won't catch it.
In informal speech, we often use going to instead of will.
If you don't take an umbrella, you're going to get wet.
We also use might or can / could in place of will. See Unit 25
We can also use imperatives in real conditions.
If you don 't knowa word, look it up in the dictionary
Sentences beginning Jf you will ... are only used when will means insist, or is used as a polite form.
If you will stay up 50 late, then of course you'll feel tired. (insist)
If you'lI wait here, I'/Isee if the manager is ready (polite)
unfess
Unless means only if not. We use it when we say that if something does not happen,
something else will happen.
Unless we deal with the global warming problem, average temperatures will rise.
provided, as fong as + present simple
Provided and as long as mean only if.
Provided / as long as we reduce energy consumption, we can slow down global warming.
in case + present simple
This describes a possible situation we want to be prepared for.
Take an umbrel/a in case it rains.
unreal conditions (conditional 2)
if X happened, Y would happen
These sentences describe what the speaker thinks would happen in an imaginary situation.
past simple would + verb
If you were on Venus, you would see the Sun rise in the west.
·1·
What would happen if the Earth stopped turning?
If the Earth didn't have a Moon, there wouldn't be any tides.
The past simple tense we use in an if-sentence does not describe past time, but unreal time.
We also use might or could in place of would. See Unit 25.
if f were you
fi We give advice with If I were you.
I wouldn't do that, if I were you. ar If I were you, I wouldn't do that.
conditionals: impossible past, wishes
impossible or past conditions (conditional 3)
if X had happened, Y would have happened
These sentences describe what the speaker thinks would have happened as a consequence of a
situation which is in the past, so is impossible to change.
On 18 June 1815 the Coalition Army under Wellington and Blucher defeated Napoleon
would have + verb past perfect
and the French army But what would have happened if Napoleon had won the battle?
would have + verb
The history of Europe would certainly have been different.
I'm sorry l didn't talk to you yesterday,but l simply didn't seeyou!
If I'd seen you, l would have said hello.
We also use might have ar could have in place of would have. SeeUnit 25.
past condition with a result in the present
if X had happened, Y would be different
We often think about past events, and their effects on the present.
If Chrishadn't gone to the hospital, he wouldn't be alive today
wishes
• about the present
When we use wish to make a wish about the present, we use the unreal past simple, as in an unreal
conditional sentence. We can also use could / was able to.
I wish I knew more about Europeanhistory
(= If I knew more about it now, I would be happier.)
I wish I could swim really fast.
• wishes about the past
When we use wish to make a wish about the past, we use the past perfect, as in an impossible past
conditional sentence.
I wish I had been present at the battle of Waterloo.
(= If I had been present at the battle of Waterloo, I would have been happy!)
• wishes with would
We also use wish with would when we want someone to do something or not to do something. This is
often because we think it is a bad habit.
I wish you wouldn't keep staring at me!
I wish Pete would phone.
• if only
We can use if only to make a stronger kind of wish about the present or the past.
If only I knew more about Europeanhistory!
If only I had studied harder!
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