One thing’s for sure, the fire _____by some cigarette butts. 
#88084
A
might cause
B
could have caused
C
must have been caused
D
should be caused
推荐题目
 Thank you for all your hard work last week. I don’t think we ______ it without you.
#87231
A
could have managed
B
can manage
C
could manage
D
can have managed
________, please try your best to solve the problem in time.
#86362
A
Ought you get into trouble
B
Must you get into trouble
C
Can you get into trouble
D
Should you get into trouble