1.Listen! Someone  knocks at the front door.=> are knocking
2. I am looking forward to go to Sam Son beach this weekend.=> going ( look forward to ving )
3. What did your child do when you came home yesterday? => was your child doing
4. The film was interesting for us seeing.  => to see
5 .My mother was make a big cake on my last birthday.=> made
6. They has bought a new computer recently.=> have
7 .My mother writed a letter to my grandmother last night ( qk đơn ) .=> wrote
8. They repaired my computer recently.( hiện tại hoàn thành )=> have repaired
9. The teacher advised the students should practice speaking English more.=> to  ( advise sb to v )
10. The tree planted here when I was ( qk ) 5 years old.=> was planted
11. Hoa lived in Hanoi since ( hiện tại hoàn thành ) she was in grade 6.=> has lived
12. My sister enjoys to read in her free time=> reading ( enjoy ving)

1 . knocks => is knocking

2 . go => going

3 . did... do =>  was .. doing

4 . seeing => to see

5 . was make => made

6 . has => have

7 . writed => wrote

8 . repaired => have repaired 

9 . should => to

10 . planted => was planted

11 . since => when

12 . to read => reading