1.     Tìm nguyên tố X (cho biết tên và ký hiệu), biết:

a. Nguyên tử X nặng gấp 2 lần nguyên tử nguyên tố Oxi.

b.     Nguyên tử cacbon nhẹ hơn nguyên tử X 0,5 lần .

Complete the sentences,using  “should” or “shouldn’t”.

9. The candidates_________ be here before 10am, or they will be disqualified.

10. You _______learn about some cultural features of the country you are going to visit.

11. Mary ___________take any pills befor seeing the doctor.

12. __________James apply for the job at this company? Yes, he should.

13. How much time __________ I spend on this task?

14. Old people _______work too hard. They need an abundance of time to relax.

15. Parents_________ let their children expose to smartphones at an early age.

Correct the errors in each sentence

11. My sister doesn’t mind to look after my cat.

12. Jim dislikes going to the library because he likes reading books.

13.  I prefer to not go out today.

14. I used to like watching cartoons on TV.

15. Does Mrs.Smith enjoy to cook?

16. Mary hates doing the housework and take after her baby sister.

17.  In my freetime, I love to do DIY with my sister.

18. Josh detests to socialise with his co-workers.

19. Which movie does he fancy to watch?

20. I prefer hanging out with friends to playing computer games.

Cho CTHH của những hợp chất sau: K(NO₃)₂; HCl; H₂SO₄; Al₃PO₄; Ba(OH)₂; NaSO₄; CaO; K₂CO₃. Hãy chỉ ra CTHH nào đúng, CTHH nào sai và sửa công thức sai thành công thức đúng.