21．The earthquake took place on_____ Friday afternoon in March and did _____great damage to the country．
A．不填; 不填 B．a； a C. a; 不填 D．the; a
22．Everyone who helps in the business will surely get their _____ in the profits．
A．shares B．attention C．duties D．concern
23．They can't afford to buy the latest equipment at present．_____, they keep trying new ways to improve efficiency．
A．Meanwhile B．Otherwise C. Nevertheless D．Furthermore
