Could/was able to

Complete the sentences using could, was/were able to, or couldn´t, wasn´t / weren´t able to.

1. __________ he understand what you were talking about? 

2. My grandfather __________ walk without any help last night. 

3. When she was 5 years old, she __________ speak Russian quite well.

4. They __________ get tickets to the Roling Stones concert last Saturday.

5. She __________ enjoy the concert because of the excessive noise. 

6. They had a spare key so they __________ start the car. 

7. He __________ to convince the police that he was not guilty. 

8. A little boy fell into the river but some men __________ rescue him. 

9. When I was younger, I __________ stay up all night and not to get tired.

10.The fire was spreading but they __________ get out of the building.

1. Could
2. was able to
3. could
4. weren't able to, couldn't
5. wasn't able, couldn't
6. were able to
7. was able to
8. were able to
9. could
10. were able to