--___do you clean the reading room? ---Every two or three days.
#25020
A
How long
B
How far
C
How soon
D
How often
推荐题目
Light-to-moderate smokers were ________ to die of sudden heart problems than those who had never smoked. 
#22215
A
as twice likely
B
twice more possible
C
twice more likely
D
as twice possible
We’ll go early.     ,we may not get a seat.
#24007
A
Otherwise
B
Meanwhile
C
However
D
Besides
They all looked ____ at the master and felt quite _____.
#24764
A
sad; sad
B
sadly; sadly
C
sad; sadly
D
sadly; sad