If … then …
A conditional sentence has two parts: the if-clause (the condition) and the main clause (the result). The tense you use shows how real or imaginary the idea is.
If-clause
If it rains tomorrow,
Result
we’ll stay at home.
First conditional: a real possibility
Rule
If + present simple, will + base verb
- Possible in the real future: If you study, you will pass.
- We can also use can, may, might, should or an imperative in the result: If you see Tom, tell him I called.
- Never put will in the if-clause: “If it will rain” is wrong → If it rains…
Second conditional: imaginary or unlikely
Rule
If + past simple, would + base verb
- Imaginary now or unlikely in the future: If I had a car, I would drive to work.
- After I / he / she / it we often say were (If I were you… is advice).
- The past tense here is not about past time; it shows the situation is not real.
1st: real
- If it rains, I will take an umbrella.
- If she studies, she will pass.
2nd: imaginary
- If I won the lottery, I would buy a house.
- If I were you, I would apologise.
Useful extras
| Word | Meaning | Example |
|---|---|---|
| unless | if … not | Unless you hurry, you’ll be late. (= If you don’t hurry…) |
| as long as / provided that | only if | I’ll lend it as long as you return it. |
| in case | because it may happen | Take a coat in case it gets cold. |
Lots of examples
- If you heat ice, it melts.Zero conditional: always true.
- If the weather is nice, we will go to the beach.First conditional.
- If I miss the bus, I will be late.Real possibility.
- If you don’t hurry, you will miss the train.Negative.
- Unless you study, you won’t pass.Unless = if not.
- If I had more time, I would learn French.Second conditional.
- If she were my sister, I would help her.Were after she.
- What would you do if you lost your job?Second conditional question.
- If I were you, I would see a doctor.Advice.
- If it doesn’t rain, we might have a picnic.Might for a weaker result.
- I wouldn’t go there alone if I were you.Negative result.
- If they offered me the job, I would probably accept.Unlikely but possible.
Don’t say / Say
Don’t sayIf it will rain, I will stay home.
SayIf it rains, I will stay home.Why: No will in the if-clause.
Don’t sayIf I would have money, I would travel.
SayIf I had money, I would travel.Why: No would in the if-clause.
Don’t sayIf I was you, I would go.
SayIf I were you, I would go.Why: Were is the standard form after I in advice.
Don’t sayUnless you don’t hurry, you’ll be late.
SayUnless you hurry, you’ll be late.Why: Unless already means if not.
Don’t sayIf I see him, I would tell him.
SayIf I see him, I will tell him.Why: Keep the pairs matching: 1st = will, 2nd = would.