White-collar workers in China are willing to postpone their retirement age ______ blue-collar workers prefer to retire early.
A. when B. while C. though D. since
“Got it?” Professor Smith says, “______, let’s move on to the next part.”
A. If not B. If anything C. If ever D. If so
By accepting lower prices, organizers can sell tickets that would ______ go unsold.
A. therefore B. otherwise
C. instead D. however
The lack of health facilities and necessary protection for medical workers partly ______ the epidemic (蔓延) of Ebola.
A. accounted for B. headed for
C. called for D. sent for
Dozens of people were waiting with a camera for ______ seemed like hours, hoping to catch a glimpse of the US First Lady, Michelle Obama.
A. that B. when C. which D. what
— Can I make an appointment with Dr. Smith this afternoon?
— Sorry, I’m afraid he is not ______ because he has a patient to operate on.
A. convenient B. available
C. accessible D. valid
