How he _______ get out of the prison ______ a mystery.
#87966
A
could; is
B
can; is
C
was able to; remains
D
able to; remain
推荐题目
. If only I ________ how to operate an electronic computer as you do. 
#89384
A
had known
B
would know
C
should know
D
knew
If my lawyer ______ here last Friday, he _____ me from telling the truth.
#87567
A
had been; would have prevented
B
had been; would prevent
C
were; would prevent
D
were; would have prevented