1. 5.8 More on Couldn’t Have
Page 215

2. couldn’t + base form
and
couldn’t have + past participle
have different meanings:

3. couldn’t + base form means that it
didn’t happen because it wasn’t
possible:

4. Examples:
I couldn’t come to class last week
because I was sick.
He couldn’t find a job, so he decided to
go back to his country.
We couldn’t go swimming because
there was thunder and lightning.

5. couldn’t have + past participle is
used to express disbelief in what
someone is saying:

6. Example:
My neighbor says that my dog bit
her, but it couldn’t have been my
dog because I never let mine
outside off-leash.

7. Example:
A: My parents voted for Kennedy in
1964.
B: What? They couldn’t have voted
for him in 1964. He died in 1963

8. Example:
A: I think I saw your brother at the
library yesterday.
B: It couldn’t have been him. He’s in
Europe on vacation.

9. Compare:
a. I couldn’t vote in the
last election because I was
out of town.
The speaker didn’t vote
because he/she was out of
town.
b. You say you voted in the
last election? You couldn’t
have voted because you
weren’t a citizen at the
time.
The speaker doesn’t
believe that the other
person said.

10. Compare:
a. I couldn’t move the
refrigerator myself, so my
brother helped me.
The speaker didn’t move
the refrigerator alone. It
was impossible.
b. You say you moved the
piano by yourself? You
couldn’t have moved it by
yourself. It’s too heavy for
one person.
The speaker doesn’t
believe that the other
person said.

11. Couldn’t have done something is
also used when showing gratitude
or appreciation for something, or
for someone’s help:

12. Example:
Thanks so much for helping me
paint my house. I couldn’t have
done it without you.

13. Example:
I couldn’t have found this place
without my GPS.