Trees ____ fight air pollution．They are natural air conditioners．
#78302
A
should
B
must
C
need
D
can
推荐题目
－Why are you looking so worried? Is there anything I can do for you?－The computer break down when I nearly finished my composition.
#62970
A
can
B
should
C
must
D
dare
--- _______ I come back before 6 o’clock?---No，you _______．But you _______ be back later than 7 o’clock．
#76770
A
Need；must；must
B
May；mustn’t；can’t
C
Can；can’t：can’t
D
Must；needn’t；can’t
The door ________ open, no matter how hard she pushed.
#62946
A
shouldn’t
B
couldn’t
C
wouldn’t
D
mightn’t
According to the rules of Daddy, where are we going?, nobody _______ take along with them cash and cell phones.
#62658
A
must
B
may
C
will
D
shall
Must we finish all the homework today or tomorrow? – You ____ worry about it. You may hand it in next week.
#74646
A
mustn’t
B
can’t
C
needn’t
D
shouldn’t