English Grammar: Understanding Conditional Sentences

First Conditional

Use: To talk about a result that will or won't occur in the future if a condition takes place.

Structure: [IF + PRESENT SIMPLE] / [FUTURE SIMPLE]

• If you study harder, you will pass your exams.
• If she eats less chocolate, she won't have so many spots.
• If we do more exercise, we will be fit.

Changing Clause Order

You can change the order of the clauses:

• You will pass your exams if you study harder.
• She won't have so many spots if she eats less chocolate.
• We will be fit if we do more exercise.

Important Punctuation

When the clause starts with IF, we put a comma after the condition.

• If she arrives early, we'll go to the cinema.
• We'll go to the cinema if she arrives early.

Second Conditional

Use: To talk about a hypothetical situation or to give advice.

Structure: [IF + PAST SIMPLE] / [WOULD + INFINITIVE]

• If you studied harder, you would pass your exams.
• If she ate less chocolate, she wouldn't have so many spots.
• If we did more exercise, we would be fit.

Changing Clause Order

• You would pass your exams if you studied harder.
• She wouldn't have so many spots if she ate less chocolate.
• We would be fit if we did more exercise.

Exception: The Verb To Be

When the verb of the condition is TO BE, we use WERE for all persons (singular and plural).

To give advice we use: If I were you...

• If I were you, I would sign the contract.

Third Conditional

Use: To talk about something that can never happen because the time has already passed.

Structure: [IF + PAST PERFECT] / [WOULD + HAVE + PAST PARTICIPLE]

• If you had studied harder, you would have passed your exams.
• If she had eaten less chocolate, she wouldn't have had so many spots.
• If we had done more exercise, we would have been fit.

Changing Clause Order

• You would have passed your exams if you had studied harder.
• She wouldn't have had so many spots if she had eaten less chocolate.
• We would have been fit if we had done more exercise.

Using Unless

Unless = If not in the condition clause.

Use: If you don't fulfill the condition, you won't be able to see the result.

• Unless you leave now, you'll miss the bus. (If you don't leave now, you'll miss the bus.)
• Unless you studied, you wouldn't pass the exam. (If you didn't study, you wouldn't pass the exam.)