By the time Jack returned home from England, his son            from college.
#101871
A
graduated
B
has graduated
C
had been
D
had graduated
推荐题目
Look at the timetable. Hurry up! Flight 4026 ____ off at 18:20.
#100325
A
will be taken
B
took
C
takes
D
has taken
How can I ever concentrate if you ________ continually ________ me with silly questions? 
#104794
A
have…interrupted
B
had interrupted
C
are…interrupting
D
were…interrupting
The hotel wasn’t particularly good. But I ________in many worse hotels. 
#99891
A
was staying
B
stayed
C
would stay
D
had stayed