4. Third Conditional

The contrary-to-fact past conditional (sometime referred to as the "third" conditional, conditional 3) is used to refer to contrary-to-fact past events [19]. Type 3 conditionals assume something purely imaginary in the if-clause and consider the imagined consequences in the main clause. In this respect they are like Type 2. However Type 3 conditionals refer to consequences which did not and could not (now) ever happen because they refer to something that didn’t happen in the past. They are hypothetical conditions [6; 288]. The past perfect is used in the condition clause and “would” + perfect infinitive is used in the main clause [5; 25]:

If I had worked harder at school, I d have got a better job. If I hadn't been wearing a raincoat, I would have got wet.

If you had called me, I would have come.

If it had rained, we would have stayed at home.

We use Type 3 conditionals to speculate about a range of possibilities from what might have been reasonably expected to what would have been completely impossible.

Basic forms of Type 3 conditionals [6; 287]:

'if'-clause: main clause:

past perfect 'would have/should have'

Imagined condition imagined outcome

be If I had been taller I would have joined the police force.

have: If I had had any sense, I would have kept quiet about it.

Past perfect. If we had gone by car, we would have saved time.

Past perfect progressive. If I had been trying harder I would have succeeded.

could have If I could have stopped there wouldn't have been an accident.

We often use 'If I had been you/in your position' expressions to describe a course of action we would have followed in someone else’s position:

If I had been you/in your position, I’d have accepted their offer.

(This means You should have accepted their offer)

We can also use these expressions to refer to somebody else: If I had been Jane, I’d have walked out on him years ago.

We often use 'If it hadn't been for' expression to explain why something didn’t happen in the past: If it hadn't been for the rain, we would have had a good harvest.

Inversion with 'had' in Type 3 conditionals

The form Had (he) is a formal variation of If (he) had:

Had the management acted sooner, the strike wouldn’t have happened.

A negative inversion is possible with the full form

Had it not been for the unusually bad weather the rescue party would have been able to save the stranded climber (Not *Hadn’ t*)[6; 288].

In the main clause of Type 3 conditional sentences we may use modal verbs:

'if'-clause: past perfect tense main clause: modal

imagined condition imagined outcome

If he had known the facts he could have told us what to do.

If he could have got the facts might

Another modal can replace would in Type 3 conditionals e.g. when we feel that the imagined consequences were less likely or when we are referring to ability, possibility, etc:

imagined condition imagined outcome

If he had been here yesterday he could have told us (ability).

If he had been here yesterday he might have told us (possibility). If he had received a present he should have thanked her (duty).

Progressive and perfect combinations with modals are possible: If he had been here he could have been helping us in the shop. If she had been here she could have met my sister [6; 289].

5. Mixed Conditional

In the English language one can come across mixed conditionals which are those unreal conditional sentences whose time in the if-clause is different than the time in the main-clause. Let's first have a look at unreal conditional sentences:

If she were shorter, she would be more attractive. I am busy next week. If I had time, I would come to your party. If they hadn't trained hard, they wouldn't have won.

As you can see, they refer to the same time. If we mix the sentences, we get mixed conditionals.

Unreal Past and Unreal Present

• If my father hadn't lost his keys, we wouldn't have to wait until he finds them. (But my father lost his keys and therefore we have to wait until he finds them).

• If I had installed an antivirus, my computer would be so slow now. (But I didn't install an antivirus and therefore my computer is so slow now).

• If our house had been broken into, we would be very sad. (But our house wasn't broken into and we aren't sad).

Unreal Present and Unreal Past

• If I were smarter, I would have graduated from Stanford. (But I am not smarter and therefore I didn't graduate from Stanford.)

• If Mary weren't a snob, she wouldn't have had so many parties this year. (But Mary is a snob and therefore she had so many parties this year.)

6. ‘If...not’ and ‘unless’

If not and unless are sometimes interchangeable but there are occasions when it is impossible to use one in place of the other

When ‘if...not’ and ‘unless’ are interchangeable

Both if not and unless can be used in negative Type 1 conditionals without a noticeable change of meaning:

If you don't change your mind I won’t be able to help you.

Unless you change your mind I won’t be able to help you.

However unless is stronger than If not and is sometimes preferable:

Unless the management improve their offer there’ll be a strike.

When we cannot use ‘unless’ in place of ‘if...not’

Unless always means ‘except on the condition that’ so we cannot normally use it to refer to unreal situations:

She’d be better company if she didn't complain so much.

Unless is not used in most questions and when we talk about emotions:

If you don’t pass the test, what will you do?

I’ll be amazed if Christie doesn’t win.

When we cannot use ‘if...not’ in place of ‘unless’

We often use unless in past references to introduce an afterthought The unless-clause follows the main clause and is usually separated by a dash rather than a comma:

I couldn t have got to the meeting on time — unless of course I had caught an earlier train.

This means the speaker didn’t get to the meeting. He could only have done so by catching an earlier train. If we use if not in place of unless in the above sentence we get

I couldn’t have got there if I hadn't caught an earlier train.

The sentence now conveys the exact opposite meaning: the speaker did get to the meeting because he did catch an earlier train [6; 289].

‘If’ and ‘unless’ clauses in short answers

Note how if-clauses and unless-clauses can occur in short answers: -Will you help us with all this re-decorating? -Yes, if I can. No, not unless you pay me.