21．Urban crowdedness would be greatly relieved if fares ________ on public transport were more reasonable.
A．offered B．spent C．paid D．charged
22．These articles ________ the problems of the modern world, including race relations and community development.
A．address B．avoid C．create D．correct
23．The workers agreed to ________ the strike if the company would satisfy their demands.
A．call for B．call in C．call off D．call up
24．The former Olympic champion was ________ in the quarterfinals last night when he lost 0-2 at home.
A．knocked off B．knocked out C．knocked down D．knocked over
