1... she earns a lot of money

2. If you have difficulties in learning English, you should ask your teacher for help

3. I'm interested in collecting stamp

4. If we recycle things, we'll save natural resources

5. ...care of ...

6. If you don't work harder, you'll lose your jop

7. ... I've been here

8. ..not having a lot of money, we don't buy a lot of new books

9. ..that she won't let anyone know my address

10. ...I turn off the lights before going out

11. I think we should organize a sponsored cycling race

12. Tom has just been seen

13. ..expensive as this one

14. ...he hadn't bought the second-hand car

15. Unless someone put the coal in, the fire will go out

16. If she works hard, she'll pass the exam

- Đặt n_Fe=a (mol); n_Mg=b (mol)

- n_H2=0,3 (mol)

pư: Mg+2HCl --> MgCl2 +H2

      Fe+2HCl --> FeCl2 +H2

=> hệ: 56a+24b=13,6

           a+b=0,3

=> a=0,2 (mol) ; b=0,1 (mol)

- Bảo toàn Fe =>  n_Fe2O3=0,1 (mol)

- Bảo toàn Mg => n_MgO=0,1 (mol)

=> m_rắn=20 (g)

Thanks :33

1. C

2. C

3. C

4. A

5. B

6. C

7. A

8. C

9. B

10. B

- Xét: \(\Delta\)'= [-(m-1)\(^2\)]-(m\(^2\)+m-1)=m\(^2\)-2m+1-m\(^2\)-m+1=-3m+2

- Để pt có nghiệm

<=> \(\Delta\)' \(\ge\) 0

<=> m\(\le\)\(\dfrac{2}{3}\)

- Theo Viete: x1+x2=2m+2 ; x1.x2=m\(^2\)+m+1

- Có \(\dfrac{1}{x1^2}+\dfrac{1}{x2^2}=\dfrac{x1^2+x2^2}{\left(x1.x2\right)^2}=\dfrac{\left(x1+x2\right)^2-2x1.x2}{\left(x1.x2\right)^2}\)

theo Viete (bạn tự thay vào nhé)

-Gọi số vịt trong trại chăn nuôi là a (con)

- Vì số gà bằng \(\dfrac{2}{5}\) số vịt

=> số gà là: a:\(\dfrac{2}{5}\)=\(\dfrac{5}{2}\)a (con)

=> tổng số gà và vịt là: a+\(\dfrac{5}{2}\)a=266

=> a=76

=> số gà là: 190 (con)

Vậy có 190 con gà và 76 con vịt trong trại chăn nuôi

1. Can you tell me the best way to learn new words?

2. We should learn how to use words by putting it into example sentences

3. I always write the words that I should learn in an extra blackboard

4. I always write the words that I should learn in a small notebook

5. People who have good memory can learn language more easily

6. Jazz has become popular in the US since the 1920s

7. I'll call you in Friday afternoon at about 2:30

8. The first man to walk on the Moon ??? (câu này mình thấy hơi lạ)

9. I used to stay on a farm with my granparents and my parents

10. We're going to see the movie Dream City at 7:00 this evening

D. 

1. am hungry/ to eat

2. is/ is

3. goes/ is shining

4. Will Mary go

5. is

6. learm

7. to drink

8. You're writing

9. doesn't drink

10. bought

11. is helping

12. was/ missed

13. needed

14. to talk/ talking

15. phoned/ haven't seen

16. is coming to see

17. went

18. is raining

19. warms/ gives

20. is running

21. goes

22. have never worked

23. meet

24. are/ going

25. doesn't do

26. Is/ doing

27. is/ will go

28. Have- seen

29. watches

30. Have/ seen

31. will go

32. have

33. has been working/ has worked

34. is raining

35. don't economise