21．Japan's refusal to release Chinese fishing boat captain had already caused_____ damage to Sino-Japanese bilateral contacts（双边关系）．
A．the; 不填 B．a; 不填
C．a; a D．the; the
22．Paper produced every year is the world's production of vehicles．
A．the three times weight of B．three times the weight of
C．as three times heavy as D．three times as heavier as
