Nowadays scientists are working hard to find out ______ to do with air pollution.
#37100
A
how
B
why
C
when
D
what
推荐题目
_______ the teachers in their school is about 200 and one fourth of them are _______ teachers. 
#37030
A
A number of; women
B
A number of; woman
C
The number of; women
D
The number of; woman
Do you look       Sam?
#43369
A
the same as
B
same as
C
the same
D
the same so
When the boy got his favourite bike, he was on top of the world.
#42553
A
very hungry
B
very satisfied
C
very angry
D
very disappointed