Present Perfect / Past

The answers to the questions above are as follows:

1. b (have been studying)

2. a (rang)

3. d (already knew)

4. b (have been learning)

5. c (have visited)

6. c (I've had)

7. d (I'd been looking)

8. c (I've known)

9. a (I saw)

10. c (have you been)

11. c (was wondering)

12. d (have never been)