Introduction
A conditional sentence is usually composed by two parts: the if-clause (or conditional clause) that expresses the condition, and the main clause that expresses the consequence of that condition.
We use the third conditional to talk about situations that did not happen in the past and the supposed results cannot occur anymore.
Form
The third conditional is a sentence created by two clauses, the if-clause (we can start the clause with if or when) and the main clause.
We use the past perfect in the if-clause (although we are talking about a future condition), and the past conditional (would have + past participle) in the main clause.
The order of the sentences does not change the meaning, therefore there are two ways of forming these expressions:
| IF-CLAUSE (CONDITION) | (,) | MAIN CLAUSE (CONSEQUENCE) |
|---|---|---|
| If + past perfect | , | would have + past participle |
or
| MAIN CLAUSE (CONSEQUENCE) | IF-CLAUSE (CONDITION) |
|---|---|
| would have + past participle | If + past perfect |
Example
- If I had known how to cook, I would have baked a cake.
- I would have talked to him, if I had had the courage.
- They would have become managers, if they had studied harder.
- If I had lost weight, I would have fit in my summer clothes.
- I would have bought a new car, if I had won the lottery.
- If they had robbed the corner shop, they would have gone to prison.
Use
We use the third conditional to talk about:
- situations that did not happen in the past, and so cannot change;
- situations that could have happened in the past and that did not happen.
Summary
A conditional sentence is usually composed of two parts: the if-clause (or conditional clause) that expresses the condition, and the main clause that expresses the consequence of that condition.
We use a third conditional to talk about situations that for some reason did not happen in the past and the supposed results cannot occur anymore in the present.
The structure is: we start with the word if followed by a past perfect clause, a comma and a clause with would have and a past participle. We can also start with the clause with would have and a past participle followed by the word if followed by a past perfect clause (we do not use a comma here).
For example:
— “If I had known we needed groceries, I would have gone shopping.” / “I would have gone shopping if I had known we needed groceries.” = I did not know we needed groceries, otherwise I would have gone. It happened in the past.
♦ “If I knew we needed groceries, I would go shopping.” = If we use the second conditional, the sentence means that I do not now if we need groceries, otherwise I would go. We talk about a future situation that is unlikely to happen.
Let’s revise this content within the {Form} section. Take a look at the {Example} section that shows its use within a context.