Trees ____ fight air pollution．They are natural air conditioners．
#78302
A
should
B
must
C
need
D
can
推荐题目
If Doric continue doing things like that, he _______ face the music one day！
#63270
A
can
B
should
C
would
D
shall
---I want to know if I can smoke here?---No, you _________. Could you see the sign “NO SMOKING” there?
#75545
A
needn’t
B
couldn’t
C
won’t
D
mustn’t
I’m sorry，boy ,you __________see this film. It is for adults only.
#63579
A
ought to
B
can’t
C
won’t
D
don’t
It’s said that there’re plenty of hotels in that town. There ______ be any difficulty for you to find somewhere to stay today.
#62543
A
wouldn’t
B
mustn’t
C
shouldn’t
D
needn’t