Jaki to czas?

1. Peter could swim when he was six.
2. John was at home last night.
3. John was playing computer games all night.
4. We weren’t at home yesterday.
5. We weren’t doing anything special last Saturday.
6. Peter read an interesting book yesterday.
7. Peter was reading an interesting book yesterday.
8. Martha and Nelly were learning a new English tense last Monday.
9. Martha and Nelly learned a new English tense last week.