8. My grandfather is too weak to lift the box
9. My father allowed me to use his car
10. The police watched they got out of the car
11. They let him write a letter to his wife
12. I heard they talked in the next room
13. The customs officer made him open the briefcase
14. The boy saw the cat jumped through the window
15. Do you think the company will make him pay some extra money
16. I felt the animal moved towards me
17. Do you think her parents will let het go for a picnic
18. This Maths problem is too difficult for him to solve it
19. Do you enjoy playing football
20. She suggests that we should go to Vung Tau for a picnic