21£®— I hear that Mary won the prize of the physics contest£®

       —______ She was not interested in it at all£®

       A£®So what?           B£®Why not?          C£®You're kidding!                          D£®I think so£®

22£®While ______ peace — keeping is the UN' s main duty, it also has programs for ______ education, better health and business in the world£®

       A£®the;an               B£®²»Ìî;the           C£®²»Ìî;an             D£®²»Ìî;²»Ìî

23£®—The last one ______ cleans the room£®

       —Agreed!

       A£®arrived              B£®arrives              C£®arriving              D£®to arrive