couldn
v. A1 Beginner couldn
v. the short way to write 'could not' or 'could not have'. You use it to say that you were not able to do something or that something did not happen.
v. the contracted form of 'could not' or 'could not have'. Used to express inability or to indicate that an action did not occur in the past.
I couldn't find my keys this morning.
We couldn't finish the report on time because the printer broke down during the final hour.
The researchers couldn't have predicted the rapid shift in public opinion that occurred just days before the election was called.