When it ______ research into heart disease and its effects on the body, we do not have adequate substitutes for the use of animals.
A. refers to B. related to C. comes to D. talks to
Would it be ___ for you to pick me up at four o’clock and take me to the airport?
A. free B. vacant C. handy D. convenient
—You speak very good French!
—Thanks. I ______ French in Sichuan University for four years.
A. studied B. study C. was studying D. had studied
We should consider _______ use can be made of such a piece of cloth.
A. what B. that C. how D. which
—He got his first book published. It turned out to be a bestseller.
—When was ________?
—______ was in 2000 when he was still in college.
A. that; This B. this; It C. it; This D. that; It
People working 10 or 11 hours a day are more likely to suffer from health problems than _____who go off duty after eight hours.
A. those B. that C. these D. them
