21 D

22 D

23 A

24 B

25 C

26 D

27 A

28 A

29 B

30 C

1)

Chất oxi hóa : $O_2$

Chất khử : $P$

2)

Chất oxi hóa : $HCl$

Chất khử : $MnO_2$
3)

Chất oxi hóa : $H_2SO_4$

Chất khử : $Al$

4)

Chất oxi hóa : $H_2SO_4$
Chất khử : $Fe(OH)_2$

5)

Chất oxi hóa : $H_2SO_4$

Chất khử : $FeO$

6)

Chất oxi hóa : $O_2$

Chất khử  :$NO_2$

1 We are looking for cheap, clean and effective sources of energy

2 We will use it to provide electricity for the....world

3 It will be stored for a long time

V

1 The festival is held to thank the Rice God for the crop

2 The power station will be rebuilt at the beginning of next year

3 They won't burn fossil fuels for energy....

1,We are looking for clean, cheap, effective types of energy

2,We will use it for hit the water

3,For a long time

1The festival is held to thank the Rice God for the crop

2The power station will be rebuilt at the beginning of this year

3,People won't burn fossil fuels for energy in the future

1 am not permitted

2 makes

3 are expected

4 doesn't let

5 was paid

6 was designed

7 was rumoured

8 ordered

9 are often shone

10 is lit

11 Is your health worsen

12 promised

13 were covered

14 often make

15 was moved

Sao ko ai giúp mình nhỉ 

1 can you=>can't you

2 doesn't=>didn't

3 will=>will they

4 this=>it

5bought=>buying

6  right

7 does=>doesn't
8 right