1. don't have to

2. musn't

3. doesn't have to 

4. musn't

5. musn't

6. don't have to

7. musn't

8. doesn't have to

Chúc bạn học tốt hen!!

46. I last saw him 2 months ago.

47. The last time I went to a concert was over a year ago.

48. I haven't really enjoyed myself since my birthday party.

49. My father hasn't seen my uncle far nearly 20 years.

50. How long is it since you learnt to drive.

51. I haven't gone swimming was since we were in Spain.

52. It's weeks since you last tidied this room.

53. I haven't been to a night club before.

❆ Để 56a3b⋮4 thì b=6

❆ Để 56a3b⋮9 thì (6+5+3+6+a)⋮9

⇒(20+a)⋮9→a=7

✔ Vậy số cần tìm là: 56736.

1. will miss

2. visit

3.went

4.is performing

5.hasn't driven

6.was cancelled

7.will you go

8.see

9.to climbing

10.throwing

40:2³+3.5²-1²⁰²¹=40:8+3.25-1

                           =5+75-1

                           =80-1

                           =79

1. Has been cleaning

2. Hasn't bought

3. Has been gardening

4. Have been waiting - hasn't arrived

5. Has written

6. Have lived

7. Has gone

8. Has taught

9. Has been writting

10. Have seen

11. Have you known - have known

12. Have been building

13. Have studied

14. Have been running

15. Has played

Bài 4: Cho biểu thức \(M=12-x^3+6x-x^2-4x+x^3+2x^2\)

^{a) Thu gọn và sắp xếp đa thức theo lũy thừa giảm dần của biến.}

^{b) Biết rằng M_min=M_o}⇔x=x_o. Tính giá trị biểu thức b+2M_o-9_xo.