1. We began listening to music at 4pm.
→ We have been listening to music since 4pm.

2. I left there last month.
→ I haven't been there since last month.

3. When did you live here?
→ How long did you live here?

4. When did you know her?
→ How long have you known her?

5. How long have you written this book?
→ When did you start writing this book?

6. Ba has worked in this factory since he was 18.
→ Ba started working in this factory when he was 18.

7. It is the first time Tom has sung.
→ Tom has never sung before.

8. Ba has never listened to classical music before.
→ This is the first time Ba has listened to classical music.

9. Nam has never seen her before.
→ It is the first time Nam has seen her.

10. I have never talked to him before.
→ It is the first time I have talked to him.

11. It is the first time Ba has killed chickens.
→ Ba has never killed chickens before.

12. It is the first time she has eaten apples.
→ She has never eaten apples before.

13. I haven't seen you for three years.
→ It is three years since I last saw you.
→ The last time I saw you was three years ago.
→ I last saw you three years ago.

14. I haven't watched TV for a month.
→ It is a month since I last watched TV.
→ The last time I watched TV was a month ago.
→ I last watched TV a month ago.

15. It is a week since I last played soccer.
→ I last played soccer a week ago.
→ The last time I played soccer was a week ago.
→ I haven't played soccer for a week.