Số người làm trong 1 ngày:

10 x 7 = 70 (người)

Số người làm trong 5 ngày:

70 : 5 = 14 (người)

ĐS: 14 người

A

D

= \(-\left(x^2+4xy+4y^2\right)\)

= \(-\left(x+2y\right)^2\)

Lịch kiểm tra là thông tin, kết luận của Khoa là dữ liệu.

Lịch kiểm tra và kết luận của Khoa đều là thông tin.

Lịch kiểm tra là dữ liệu, kết luận của Khoa là thông tin.

Những dòng chữ, con số thể hiện ngày tháng năm, giờ trên lịch kiểm tra là thông tin.

36.   The last time I ate sushi was the last summer.

ð  I have eaten sushi since last summer.                                                       

37.   I last saw her on Monday.

ð  I have seen her on Monday.                                                                       

38.   I started collecting stamps last winter.

ð  I have collected stamps since last winter.                                                                

39.   I haven’t watered this tree for a week.

ð  The tree haven't been watered for a week                                                                                         

40.   How long have you worked as a volunteer?

ð  When have you worked as a volunteer?                                                                                          

41.   They began playing tennis in the spring of 2012.

ð  They have been playing tennis since  spring of 2012.                                                                                  

42.   We have learned English for 10 years.

ð     English has been being learned for 10 years.                                                                                               

43.   It has been a long time since we last met.

ð    We haven't been met for a long time.                                                                              

5. It’s a week since I last saw him. (seen)

I have seen him for a week.

6. When did she move to France? (since)

How long since she has moved to France?

7. He has never seen this film before. (ever)

It’s the first time he has ever seen this film.

8. The last time he visited her was a week ago. (for) 

He has visited for a week.

9. They started eating as soon as the last guests arrived. (had)

They had waited until they started eating.

10. They started learning computing two months ago. (been)  They have been studying computing for two months.

11. It’s the fastest car I’ve ever driven. (never) 

I have never driven this fast car.

12. They haven’t come back yet. (still) 

They still come back.

13. How long is it since he broke his leg? (break)

When did his leg break?

14. It’s the first time he’s ever seen a skyscraper. (never) 

He have never seen a skyscraper before.

15. She started writing a novel a year ago. (been) 

She has been writing for a year.

16. That’s the smallest car I’ve ever seen. (small) 

I have never seen that small car. 

17. They didn’t go to bed until the programme had finished. (when)

They would go to bed when the programme finished.

1 A

1. A

2. B

3. C

4. C

5. A

6. B

7. D

8. D

1. Do you have any hobby?

2. What does you brother do in his free time?

3. He usually goes climbing mountain in the summer.

4. I enjoy playing monopoly with my friends.