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Updated: Jan 27, 2023

- we can identify six types of conditional clauses: zero, first, second, third + two mixed ones

For the start, let’s repeat what the difference is between 'sentence' and 'clause'.

I will pick you up if you call me.

All the underlined words form a sentence. This sentence consists of two clauses.

The first clause is the main clause.

The second clause is the subordinate clause, in this case marked with a conditional conjunction ‘if’.

If the main clause is written first, a comma is not used to separate these two clauses. However, if the subordinate clause is first, there must be a comma.

If you call me, I will pick you up.


If/when + subject + present simple, subject + present simple

  • when = if

  • common states or events, facts, general truths, laws, and rules

  • the situation is real and possible

  • also used to give instructions with the imperative in the main clause*

If/When we heat ice, it melts.

If/When I need money, I go to the bank.

If/When the sun shines, it is warm.

I don’t eat if/when I am not hungry.

*If your dad comes home, tell him to call me immediately.

*Look at me if I talk to you.


If + subject + present simple, subject + will / be going to

  • if

  • possible future states or events

  • future situations which are real or possible

If I have a chance, I will go on holiday.

If she gives up, she won't get a new job.

If it doesn’t snow, we are not going to the Giant Mountains.

  • Unless + positive verb form in present simple can be used instead of ‘if not’

Mary won’t come unless you invite her personally.

You won’t pass the exam unless you study hard.


If + subject + past simple/continuous, subject + would/could/might/should

  • unlikely or imaginary (hypothetical) states or events in the present or future

  • we use I/ he / she / it were (subjunctive) instead of ‘was’ in formal contexts

  • to give advice we often use: If I were you, I’d …

If I didn't cook, we would be hungry.

If I were you, I would go on holiday.

If Marcel had more money, he would travel around the world.

I would buy a yacht if I were a billionaire.


If + subject + past perfect, subject + would/could/might/should + have + past participle

  • imaginary (unreal) states or events in the past

If I had studied better, I would have enrolled at a better university.

Paula could have stopped by if she had wanted to.

Mark would have helped you if you had asked him.

When you start with the if clause, a comma follows. If it is the other way round and the main clause is at the beginning, there is no comma.

Instead of if, we can also use: if so, given, otherwise and provided (that) /providing that

We don’t use so, which is used in Czech:

Kdybych byla tebou, tak bych mu nevolala. If I were you, so I wouldn’t call him.


Sometimes you can come across sentences that are conditional but look a bit different and do not fit the preceding four types. They might be mixed. We differentiate two types of mixed conditionals:


  • A condition is in the past and a result is in the present.

3rd 2nd

If + past perfect, sb + would

If I had invested money, I would be rich now.

If I hadn’t gone skiing, I wouldn’t be sick now.


  • A condition is in the present but affects the past

  • The present conditions are about constant truths

2nd 3rd

If + past simple, sb + would have + past participle

If I weren’t so lazy, I would have helped them.

If I weren’t so careless, I wouldn’t have lost the car keys.

I would have gone to the party if I didn’t have to work. (Meaning, I had to work then as well as I still have to work now)

If Jill wasn’t so kind, I would have never talked to her. (It is about the past. I talked to her that is why would have is used.)


  • imperative: if/ when + subject + present simple, imperative

When you come, don’t knock.

Use a tissue if you sneeze.

  • will after if in polite requests

If you will wait a moment, I will call Mrs Bark.

  • to make the request even more polite use would

If you would take a seat, I will call Mrs Bark.

Connecting expressions:









1) If you are a beginner or study English alone, take the types one by one and focus mostly on the ZERO, FIRST and SECOND type. Always proceed to the next one if you can use one type with confidence without mistakes.

2) Only advanced students should pay attention to the mixed types.

3) When learning/practising 2nd and 3rd type, you may find out you have problems with past and past participle forms. I would recommend focusing on them too. You can download a list of the most useful verbs here:

And practice them here:

Past forms

Past perfect forms

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