Toán Lớp 8: 11. It isn’t necessary for Tuan to water that tree every day.
=> Tuan doesn’t __________________________________________.
12. You aren’t allowed to make noise in the library.
=> You must _____________________________________________.
13. Must he leave now?
=> Does ________________________________________________
14. It isn’t necessary for you to go to school so early.
=> You do _______________________________________________.
15. It is a good thing for you to keep the house clean and tidy.
=> You ought _____________________________________________.
16. It is a bad thing for students to make noise in class.
=> Students ought_______________________________________
17. It is not a good idea for you to put so much salt in the soup.
=> You should_________________________________________
18. I want to work as an interpreter in the future, so I am studying Russian at university.
=> Because____________________________________________________________
19. These objects are very dangerous so we must put them in locked cupboards.
=> Because_______________________________________________________
20. Ba doesn’t have a clock so he goes to school late.
=> Because_____________________________________________________________