Not until his mother came back_______.
#81003
A
he began to do his homework
B
had he began to do his homework
C
he had begun to do his homework
D
did he begin to do his homework
推荐题目
The achievements of the greatest minds in science could never have been reached________ the patient work of hundreds of others．
#83215
A
were it not for
B
had it not been because
C
had it not been for
D
if it had not been
Many provinces have been hit with smog. If _______ unsolved, the problem may lead to more serious results.
#80140
A
having left
B
to leave
C
left
D
leaving
This lecture is by no means the most boring. I’ve attended_____.
#84638
A
better
B
worse
C
the best
D
the worst
— Did you know any French before you arrived in Washington?— Never ______ it, actually.
#79862
A
had I learned
B
have I learned
C
I learned
D
was I learning
If you don’t agree to our plan, __________.
#82776
A
so will they.
B
neither will they.
C
neither they will.
D
so they won’t.