could, couldn’t or was, were able to

A girl fell into the river but fortunately we (a)   rescue her.

I (a)   walk when I was less than a year old.

My grandfather (a)   walk without any help last night.

(a)   you understand what he was saying?

My grandmother (a)   speak Spanish.

Suddenly all the lights went out. We (a)   see a thing.

The computer went wrong, but luckily Emma (a)   put it right again.

There was a big party last night. You (a)   hear the music half a mile away.

I learnt to read sheet music as a child. I (a)   read it when I was five.

People heard warnings about the food, and they (a)   move out in time.