The third conditional

 

We use the third conditional to talk about unreal situations in the past.

 

We use the third conditional to talk about:

1. things that did not happen,
2. situations like dreams or wishes with no possibility of coming true.

 

The third conditional contains:

1. An ‘if’ clause
2. A main/result clause

 

The third conditional uses the Past Perfect in the ‘if’ clause and the Past Participle in the result clause.

 

If/condition Clause	Result Clause
Past perfect	Would have + past participle

• If she had won the lottery, (‘if’/condition clause) + she would have bought a new house. (result clause)
• I would have told her about it (result clause) + if I had known. (‘if’/condition clause)

 

When we use the third conditional, we are talking about an impossible past condition. The condition was not and cannot ever be true because it is over and in the past. This also means the result is impossible because the condition is impossible.

 

Just like the second conditional, the ‘if’/condition clause has a comma at the end if it comes first. There is no comma if the ‘if’/condition clause comes second, after the result clause.

• I would have done better on the test if I had studied harder. (no comma needed because the “if” clause comes second)
• If you had tried harder, you would have won. (a comma comes after the “if” clause when it is first)

 

We can make positive, negative, and interrogative sentences using the third conditional. We can also use ‘should have‘, ‘could have‘, and ‘might have‘.

• If we had worked better as a team, we might have won the tournament.
• You could have bought that toy if you had saved your money.
• If it had rained yesterday, what would you have done?
• Your day would have been better if you had not stayed up all night playing games.

 

We can also use the contracted form in each clause.

• You could’ve bought that computer if you’d saved your money.
• If she’d tried harder, she’d have done better.
•  If you hadn’t slept in, you wouldn’t have missed your flight.

 

Let’s summarize:

ZERO CONDITIONAL: General truths
If + Simple Present	Simple Present
If this thing happens	that thing happens.
FIRST CONDITIONAL: A possible condition and its probable result
If + Simple Present	Simple Future
If this thing happens	that thing will happen.
SECOND CONDITIONAL: A hypothetical condition and its probable result
If + Simple Past	Present Conditional or Present Continuous Conditional
If this thing happened	that thing would happen. OR  that thing would be happening.
THIRD CONDITIONAL: An unreal past condition and its probable result in the past
If + Past Perfect	Perfect Conditional
If this thing had happened	that thing would have happened.OR that thing would have been happening.