THIRD CONDITIONAL EXERCISE 2 (ESL)
B1–B2 · IntermediateUseful for:✓ Cambridge B2/C1
This second third conditional exercise focuses on recognizing and avoiding the most common mistakes with this structure — particularly confusing would have and had, and getting the correct clause order. Start with exercise 1 if you haven't already.
Need a refresher? Review the grammar ↓
Choose the correct option to complete each third conditional sentence.
1. If my aunt hadn't rested, she _________ tired.
Correct answer: would have been — third conditional result — if + past perfect → would have + past participle.
2. Mary _________ him if she had known about his financial problems.
Correct answer: would have helped — third conditional result — if she had known → would have helped.
3. I would have gone with Robert if he _________ me.
Correct answer: had asked — third conditional if-clause — past perfect required: if he had asked.
4. We ________ the raccoon if Amelia hadn't pointed it out to us.
Correct answer: would not have noticed — third conditional negative result — if + past perfect → would not have + pp.
5. If they ________ that expensive car, they would have more money now.
Correct answer: hadn't bought — third conditional if-clause — past perfect negative: if they hadn't bought.
6. If I had known you lived in Toronto now, I ________ you!
Correct answer: would have visited — third conditional result — if I had known → would have visited.
7. If you ________ for food, you would not have been hungry now.
Correct answer: had stopped — third conditional if-clause — past perfect required: if you had stopped.
8. If I had known you were on vacation, I ________ you.
Correct answer: would not have called — third conditional negative result — if I had known → would not have called.
9. If I ________ my cat, I would have been miserable.
Correct answer: hadn't adopted — third conditional if-clause — past perfect negative: if I hadn't adopted.
10. We would have seen Russell if he ________ at the meeting.
Correct answer: had been — third conditional if-clause — past perfect required: if he had been.
Finished this series? Try First Conditional — Exercise 1 →.
GRAMMAR REVIEW! The third conditional — common mistakes to avoid
The third conditional has a longer structure than the first or second, which means more opportunities for errors. Here are the most common mistakes learners make:
1. Using would have in the if clause
The if clause must use the past perfect (had + past participle), never would have:
✗ If she would have left earlier…
✓ If she had left earlier…
2. Using will have instead of would have in the main clause
The main clause expresses a hypothetical past result, so it requires would have, not will have:
✗ She will have arrived on time.
✓ She would have arrived on time.
3. Mixing the third conditional with the second
The third conditional refers to the past; the second refers to the present or future. They are not interchangeable:
✗ If I had more time, I would have called you. (mixed — inconsistent)
✓ If I had had more time, I would have called you. (consistently past)
Remember: Both clauses must refer to the same time frame.
The third conditional has a longer structure than the first or second, which means more opportunities for errors. Here are the most common mistakes learners make:
1. Using would have in the if clause
The if clause must use the past perfect (had + past participle), never would have:
✗ If she would have left earlier…
✓ If she had left earlier…
2. Using will have instead of would have in the main clause
The main clause expresses a hypothetical past result, so it requires would have, not will have:
✗ She will have arrived on time.
✓ She would have arrived on time.
3. Mixing the third conditional with the second
The third conditional refers to the past; the second refers to the present or future. They are not interchangeable:
✗ If I had more time, I would have called you. (mixed — inconsistent)
✓ If I had had more time, I would have called you. (consistently past)
Remember: Both clauses must refer to the same time frame.
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