1. bought (MĐ1 chia thì QKĐ ⇔ MĐ2)
2. didn't come (MĐ1 chia thì QKĐ ⇔ MĐ2)
3. was (MĐ1 chia thì QKĐ ⇔ MĐ2)
4. was listening (at half-past seven yesterday night ⇒ Thì QKTD)
5. knew (MDD2 chia thì QKĐ ⇔ MĐ1)
6. took (MĐ2 chia thì QKĐ ⇔ MĐ1)
7. were sleeping.......... was doing (at midnight ⇒ Thì QKTD)
8. was standing ........... ran (QKTD + When + QKĐ)
9. took (MĐ1 chia thì QKĐ ⇔ MĐ2)
10. went ( Thì QKĐ)
11. were being ........ went (QKTD + When + QKĐ)
12. decided (four years ago ⇒ Thì QKĐ)
