Ch 16
Third Conditional
If + past perfect + would have + PP
The third conditional imagines a different past — a situation that did NOT happen, and its imaginary result.
If + past perfect, + would have + past participle ✓
Regret
If I had studied harder, I would have passed.
Different past
If she hadn't called, I wouldn't have known.
Criticism
If you had told me, I would have helped.
Zero
If + present, + present — always true
First
If + present, + will — real future possibility
Second
If + past, + would — imaginary present/future
Third
If + past perfect, + would have — imaginary past
If I had known, I would have come.
I didn't know → I didn't come
would have (certain)
If I had applied, I would have got the job.
could have (possible ability)
If I had practised, I could have played better.
might have (less certain)
If she had come, things might have been different.
If I had → If I'd
If I'd known, I would have come.
would have → would've
I would've helped you.
wouldn't have → wouldn't've
She wouldn't've said that.
In writing, use full forms: would have. In speech, contractions are natural. NEVER write would of — it's would have.
If I would have studied, I would have passed.
→
If I had studied, I would have passed.
if clause → past perfect (NOT would have)
If she had came, I would of been happy.
→
If she had come, I would have been happy.
come not came (past participle) · would have (not "of")
I had studied harder, I would passed.
→
If I had studied harder, I would have passed.
result = would + have + PP
Recap
Form
If + past perfect, + would have + PP
If I had known, I would have come.
Meaning
imaginary PAST — it didn't happen
regret, criticism, speculation
NEVER "would" in if
if + had + PP (not if I would have)
If I had studied... ✓
NEVER "of"
would HAVE (not would of)
I would have gone ✓