21.Of all ___ reasons for my decision to go abroad, my father’s advice was ___ very important one.
       A. the; /                 B. the; the                  C./; the                      D. the; a
22.Is it in this room in _____ the great writer once lived ____ he finished his last works?
       A. which; that             B. that, where             C. that; which             D. where; that