1. hadn't watched (if loại 3→ S+ had + V3/ed, S+ would (not) have + V3/ed)
2. asks (If 1→ If + S + V(s,es), S + Will/Can/shall... + V1)
3. would have had (if loại 3→ S+ had + V3/ed, S+ would (not) have + V3/ed)
4. weren't (If 2 → If + S + V2/ Ved, S +would/ Could/ Should…+ V1)