Choose the correct form of the verbs1. Why did you walk

Choose the correct form of the verbs
1. Why did you walk all the way from the station? You could phone/could have phoned for a lift.
2. I loved staying with my grandparents when I was a child. They let me read all the books in the house and told me I could/was able to go to bed as late as I wanted.
3. This carpet was priced at 500, but I could/was able to get a discount because of this little mark in the corner.
4. I couldnt have found/havent been able to find my diary for days. Its terribly inconvenient.
5. As soon as she opened the door I could/was able to see from her face that something terrible had happened.
6. Ive no idea where my brother is living now. He can/could be at the North Pole for all I know.
7. Its difficult to understand how explorers survive the conditions they encounter in the Antarctic. Im sure I cant/couldnt.
8. Why did I listen to you? I can be/could have been at home by now instead of sitting here in the cold.
9. The day started off misty, but by the time we had reached the mountain the sun had appeared and we could/were able to climb it quite quickly.