13. Mr. Sang used to ride a water buffalo ten years ago.
14. Did you use to read novels in the bedroom last year?
15. She didn’t use to watch any romantic films three years ago.
16. They used to play marbles in the yard when they were 10 years old.
17. She used to be a truck driver 15 years ago.
18. Mr. Tuan didn’t use to teach me Math last year.
19. Did he use to plant trees along the streets in the city twenty years ago?
20. Hung used to write the letters to his girlfriend before he died last month.