A

C. had =)

help me plssssssssss

2 bài nào vậy??

10. C

11. C

nhưng câu hỏi đâu?

1 C

2 D

3 C

4 C

5 C

6 B

7 D

7 C

9 A

10 A

11 C

12 A

13 A

14 D

15 D

16 A

17 D

18 B

19 D

20 C 

Anh ajakcac

2.unless

3,unless

4,if

5.if

6.unless

7.if

8.unless

B5:

1E

2H

3A

4G

5B

6C

7F

8D

B6:

2. won't stay - find

3.hoover - will make 

4.will show - wait 

\(\dfrac{8}{1\cdot3}+\dfrac{8}{3\cdot5}+...+\dfrac{8}{89\cdot91}\)

\(=4\left(1-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{5}+...+\dfrac{1}{89}-\dfrac{1}{91}\right)\)

\(=4\cdot\dfrac{90}{91}=\dfrac{360}{91}\)