Though he is ill, he has not quit _____.
| A．smoke | B．to smoke | C．smoked | D．smoking |
—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 |