The Third Conditional: B1 Exercises

Every answer with the reason behind it. Read the explanation for the ones you got right as well — that is where you find out whether you were right for the right reason.

Multiple choice questions — answers

1. If I had known about the strike, I ___ home much earlier. → would have gone

The result of an unreal past takes would have plus the past participle.

2. If the taxi had arrived on time, we ___ the flight. → would have caught

Both halves must be past: past perfect after if, would have plus participle in the result.

3. If she ___ medicine, she would be a hospital consultant today. → had studied

A past cause with a present result is the mixed conditional: past perfect after if, but plain would in the result.

4. If he hadn't dropped his phone in the sink, it ___. → wouldn't have broken

The negative result of an unreal past is wouldn't have plus the past participle.

5. If I ___ more time that week, I would have finished the report. → had had

The past perfect of have is had had. It looks like a slip and is in fact correct.

6. We ___ won the match if our goalkeeper had been fit. → could have

Could have replaces would have when the speaker means the result was possible rather than certain.

7. Which sentence is a correctly formed third conditional? → If I had known, I would have called.

Would have never belongs inside the if clause — that is the single most common error in this structure.

8. ___ I realised how late it was, I would have taken a taxi. → Had

Formal English can drop if and invert: Had I realised means exactly the same as If I had realised.

9. If they had invited me to the wedding, I ___ definitely gone. → would have

Would have plus the participle, with the adverb sitting between the two parts.

10. If you had told me the truth then, everything ___ different now. → would be

Now anchors the result in the present, so this is a mixed conditional and the result drops have.

11. She ___ have passed if she had revised the last chapter. → might

Might have expresses an uncertain unreal result — the speaker is guessing about a past that did not happen.

12. 'If we had booked earlier, we would have saved £200' implies that we ___. → did not book earlier

A third conditional always states the opposite of what really happened, so the booking was late and the money was not saved.

13. If the road ___ icy, the accident would never have happened. → hadn't been

The if clause of a third conditional is past perfect, so the negative is hadn't been.

14. I would have replied sooner if your email ___ in my spam folder. → hadn't landed

The condition is a past event that did occur, so its negative takes the past perfect.

15. Choose the mixed conditional. → If I had slept, I would feel better now.

Past perfect cause plus a present result marked by now — the two halves sit in different times on purpose.

16. If nobody ___ the fire alarm, the whole floor would have burned. → had set off

Somebody did set the alarm off, so the unreal version of that fact is the past perfect: if nobody had set it off.

17. He might not have crashed if he ___ so fast. → hadn't been driving

The past perfect continuous shows an unreal action in progress at the moment of the accident.

18. If I had been in your position, I ___ exactly the same thing. → would have done

A judgement about a completed past situation, so would have plus the past participle.

19. Which sentence expresses regret about the speaker's own past? → If I had listened, I would not be in this mess.

Only the past perfect if clause places the failure in a past that cannot now be changed.

20. We would have been on time ___ the motorway had not been closed. → if

If introduces the condition. Unless would double the negative already present in had not been closed.

Fill-in-the-blank questions — answers

1. If I had known you were ill, I ___ have visited you. → would

The result clause of a third conditional is would plus have plus a past participle.

2. If we had left at six, we ___ never have hit the traffic. → would

Would have carries the unreal past result; the adverb sits between the two words.

3. She would have accepted the job if the salary ___ been higher. → had

The if clause takes the past perfect, so had plus the past participle.

4. If the weather ___ been so bad, the ceremony would have been outdoors. → hadn't

The negative past perfect states the opposite of what really happened.

5. ___ I known about the discount, I would have bought two. → Had

Formal English inverts had and the subject and drops if entirely.

6. He ___ have been promoted if he had spoken better German. → might

Might have softens the claim: the promotion was possible, not guaranteed.

7. If I ___ enough money at the time, I would have bought that painting. → had

The past perfect of have in the if clause of an unreal past condition.

8. If you had revised properly, you ___ be retaking the exam now. → wouldn't

A mixed conditional: past cause, present result, so no have in the result clause.

9. The parcel would have arrived yesterday if you ___ given them the right postcode. → had

Past perfect after if is what marks the condition as contrary to fact.

10. If she ___ taken that flight, she would have missed the conference entirely. → hadn't

The negative in the if clause reverses what actually happened.

11. We could ___ saved a fortune if we had compared the prices. → have

Could have plus a past participle is the possible, rather than certain, unreal past result.

12. If the manager had listened to us, this ___ never have happened. → would

Would have plus the participle expresses the result that did not come about.

13. I would not have said anything if I ___ realised she was there. → had

Past perfect after if, even when the if clause comes second in the sentence.

14. If they had trained harder, they ___ have reached the final. → might

Might have keeps the outcome uncertain, which is honest about a match nobody played.

15. If I ___ been driving, the accident would not have happened. → hadn't

The past perfect continuous in negative form: hadn't been plus the -ing verb.

16. She would be fluent by now if she ___ kept up her lessons. → had

By now marks a present result from a past cause — a mixed conditional.

17. If we had booked a table, we ___ not have queued for an hour. → would

The negative result of the unreal past still uses would have, split by not.

18. If the shop ___ closed early, I would have collected the order. → hadn't

The shop did close early; the past perfect negative states the reverse.

19. You ___ have hurt yourself if you had climbed that ladder alone. → could

Could have warns about a danger that was possible but never actually materialised.

20. If the referee had seen the foul, the match ___ have ended differently. → might

Might have suits a speculation about a result nobody can now verify.

Sentence structure: word ordering — answers

1. Explain why you kept quiet about something. → If I had known, I would have told you.

Explain why you kept quiet about something.

2. Blame a cancelled service for being late. → We would have arrived earlier if the train had run.

Blame a cancelled service for being late.

3. Use the formal inversion instead of if. → Had she asked me, I would have helped.

Use the formal inversion instead of if.

4. Explain a failed exam in the third conditional. → If he had revised, he would have passed.

Explain a failed exam in the third conditional.

5. Speculate about a match with an uncertain result. → They might have won if their captain had played.

Speculate about a match with an uncertain result.

6. Build a mixed conditional: past cause, present result. → If I had studied law, I would be a judge.

Build a mixed conditional: past cause, present result.

7. Say what a little more speed would have prevented. → She would not have missed the bus if she had hurried.

Say what a little more speed would have prevented.

8. Explain a short holiday with a price problem. → If the hotel had been cheaper, we would have stayed longer.

Explain a short holiday with a price problem.

9. Point out a missed opportunity to ask. → I could have helped if you had called me.

Point out a missed opportunity to ask.

10. Criticise a failure to give notice. → If they had warned us, nobody would have panicked.

Criticise a failure to give notice.

11. Ask somebody to judge a past decision. → What would you have done in my situation?

Ask somebody to judge a past decision.

12. Use the double had, and a present result. → If I had had a map, we would not be lost.

Use the double had, and a present result.

13. Defend somebody who did not grasp the problem. → He would have apologised if he had understood.

Defend somebody who did not grasp the problem.

14. Describe a security failure and its lost result. → If the alarm had worked, the burglars would have fled.

Describe a security failure and its lost result.

15. Admit a half-hearted search with an uncertain outcome. → We might have found it if we had looked properly.

Admit a half-hearted search with an uncertain outcome.

16. Mix a past failure with a present consequence. → If you had listened, you would know the answer.

Mix a past failure with a present consequence.

17. Invert the condition in formal style. → Had we left earlier, we would have avoided the queue.

Invert the condition in formal style.

18. Credit a change to public pressure. → If nobody had complained, the rule would have remained.

Credit a change to public pressure.

19. Describe a reaction that never occurred. → She would have been furious if she had heard that.

Describe a reaction that never occurred.

20. Explain your present location by a past disruption. → If the flight had not been cancelled, we would be there.

Explain your present location by a past disruption.