All his attempts to unlock the door were , because he was using the wrong key.
#27426
A
in return
B
in vain
C
in doubt
D
in time
推荐题目
We have brought in a good grain harvest for three years_________.
#26888
A
on purpose
B
on end
C
on duty
D
on watch
If you really have to leave during class, you’d better leave____ the back door.
#25419
A
for
B
at
C
by
D
out
China now aims to boost domestic demand, and this ______ would help the global economy.
#25856
A
in short
B
on duty
C
on average
D
in turn