—Have you been to the Great Wall?
—Perhaps not in my memory. ________, it might have been during my early childhood.
A. If any B. If so C. If ever D. If not
The question that puzzled them is ____ they can get rid of the air pollution in the area.
A. how is it that B. that how C. what is it D. how it is that
Teachers have to constantly update their knowledge in order to maintain their professional _____.
A. consequence B. independence C. competence D. intelligence
“I don’t think it’s my _______ that the TV blew up. I just turned it on. That’s all.” said the boy.
A. error B. mistake C. fault D. duty
—Hi, Monica. Have you made up your mind yet?
—Well, _______. I think I’m going to take up hairdressing.
A. sooner or later B. more or less
C. better or worse D. now and then
—Look! Somebody _____ the sofa.
—Well, it wasn’t me. I didn’t do it.
A. is cleaning B. was cleaning
C. has cleaned D. had cleaned
