Conditional sentences consist of an "if" clause and a main clause. There are four types of conditional sentences: Zero conditional refers to facts that are always true. First conditional refers to likely or real possibilities in the future. Second conditional refers to unlikely or imaginary possibilities in the present or future. Third conditional refers to unlikely or imaginary possibilities in the past. The tenses used in each clause depend on whether the condition is possible, impossible, in the present, future or past.

1. CONDITIONAL
SENTENCES

2. Conditional sentences consist of two
clauses: a conditional clause (or “IF”
clause) and the main clause (or “RESULT”
clause) which is dependent on the
conditional.

3. There four basic
conditional sentence
patterns where our choice
of tense depends on:
1.- the time of the condition
(present, future or past).
2.- how possible or
impossible we think it is.
Zero conditional Possible at any
time, but most
commonly in
the present.
If your car is old, it
probably needs a
road test.
First conditional Possible in the
future.
If we don’t water
these plants, they’ll
die.
Second
conditional
Impossible in
the present.
If my eye sight was
perfect, I wouldn’t
need glasses.
Possible (but
unlikely) in the
future.
If I were rich, we’d
buy a house in NY.
Third conditional Impossible in
the past.
If you had answered
the door, she
wouldn’t have gone
away again.

4. ZERO CONDITIONAL
Used for facts that are always true. Actions that always have
the same result:
• If you study a lot, you always pass your exams.
• If you can read this, you’re driving too close to me!
You can replace IF with WHEN if we are referring to a regular
activity:
• When I eat dairy products, I get red spots on my skin.
We can use modal verbs (especially “can” and “may”),
present simple, perfect or continuous in both clauses.
We can find a similar pattern to refer to the past:
When they went to the movies, they always sat at the back.

5. TYPE I:LIKELY OR REAL
• If + present (simple, continuous or perfect), WILL/ SHALL or BE going
to. (Also future continuous or perfect)
– If you come to the party, you’ll enjoy yourself.
– If the concert is on Friday, I’m going to buy the tickets at once.
– If you arrive before 10:00, we’ll be playing in the park.
– If you continue wasting your money, you’ll have gone bankrupt in
three years.
• If + present (simple, continuous, perfect), imperative
– If you come to the party, bring some wine.
– If you have finished, come to the party.
– If you are expecting someone, tell him to join us.
• If + present (simple, continuous, perfect), modal
– If you come to the party, you must bring a bottle of wine.
– If you have finished, you can come with us
– If you are expecting someone, I can leave.

6. Other Patterns
• Requests: if + future, future
– If you’ll just wait a minute, I’ll call the manager
to help you.
• If + should/ If + happen to (less likely but possible)
– If you should see James, tell him to phone me.
– If you happen to see James, tell him to phone
me.

7. OTHER CONJUNCTIONS
• Unless= if...not. Often used in warnings.
– We’ll be late for our English lesson unless we hurry.
• As long as (or so long as)= if, on condition that.
– We’ll be on time for our lesson as long as you hurry
up.
• Provided (that)/providing (that)= if, on condition that.
– Providing (that) you lay the table, I’ll cook.
– He will pass his exam, provided (that) he studies a lot.
• In case (precaution)
– Take an umbrella in case it rains.

8. TYPE II: UNLIKELY/IMAGINARY
• If + past (simple or continuous), would/could/ might/ should + infinitive
– If you were driving from Cartagena to Cuenca, what way would you go?
(You are not driving)
– If I went to London, I could/ might improve my English (unlikely that you’ll
go but possible).
• If I were rich, I would travel around the world.
• If she was/were rich, she wouldn’t work.
• Were you really ill, I would call the doctor (formal).
To emphasise the condition is unlikely to happen:
• If the printer should break down within the first year, we would repair it.
• If you were to listen more carefully, you might understand me!
IF IT WEREN’T FOR …
• If it weren’t for his wife’s money, he’d never be a manager.
• If it weren’t for the on-the-job training, I would quit.

9. TYPE III: UNREAL/ IMAGINARY IN
THE PAST
Imaginary situations in the past.
• Used to criticise, to point out mistakes or to express a regret.
If + past perfect (simple or continuous), would/ could /might
have + past participle (or “been” + -ing)
– If I had gone to the party, I would have taken a bottle of wine.
– If the taxi hadn’t come along, you would have been waiting there for
hours.
• Had I known the results, I would have phoned you. (formal)
IF IT HADN’T BEEN FOR ...
• If it hadn’t been for your help, I wouldn’t have got the hang of it so
quickly.
• If it hadn’t been for the reshuffle of the company, it might have
gone bankrupt.