Nobody knows for sure how dinosaurs died out 65,000,000 years ago. It _______ because of sudden changes of their living conditions.
#62591
A
must have happened
B
would have happened
C
should have happened
D
might have happened
推荐题目
It is usually warm in my hometown in April, but it ________ be rather cold sometimes.
#63060
A
can
B
must
C
would
D
should
I ________worry about my weekend—I always have my plans ready before it comes.
#63400
A
can’t
B
mustn’t
C
daren’t
D
needn’t
If you _______ carry with you the belief that all you do is right, it’s none of my business.
#63245
A
should
B
may
C
can
D
must