A
C
D
A
B
B
D
C
A

lived/traveling

4.You shouldn't speak loudly in public

5.There are 6 rooms in my house

2.What about staying at home

3.The yard is large

a: =x^4-4y^2

b: 

c: 

d: 

C
B
A
A
B
C

D
A
B
C
D
A
A
C
D

lived/traveling

Nowadays our environment is seriously polluted by human's activities,write a passage(160-180 words) about the things you should do to protect the environment