21. It is ____ short distance from here to _____ shopping center, so you can walk there if you like.
A. 不填; 不填 B. a; 不填 C. the; the D. a; the
22. ––Do you think it wise for parents to do everything for their children?
––No. That’s ______ they’re mistaken.
A. whether B. when C. what D. where
23．—Did you happen to hear the recent news?
—Yes, Alice ____ the gold medal in the speech contest, which I find hard to believe．
A．wins B．won C．had won D．will win
