21.The new machine, if __________ properly, will work for at least ten years.
A. use B. using C. being used D. used
22. We shouldn’t complain about being poor--- many families are______ than we are.
A.worse off B. badly off C.well off D.better off
23. —I hear that Jason is planning to buy a car.
—I know. By next month，he __________ enough for a used one.
A.saves B. will be saving C. has saved D. will have saved
