7A
1. was
2. were
3. was
4. was
5. was
6. were
7. were
8. weren't
7B
1. We studied English yesterday
2. Did you listen to the news yesterday?
3. He didn't cook dinner yesterday
4. Did she play sport yesterday?
5. Did they work late yesterday?
6. Did I use/did you use the internet at work yesterday?
7. Did she chat with her friends yesterday?
8. Did my brother dance yesterday?