21．In China, car is becoming popular means of transportation
A．a; the B．a; 不填 C．the; the D．the; a
22． ． is expected that it will be fine tomorrow, when we can do some outdoor activities
A． As B． It C． That D． Which
23． — I regret to say that I have shouted at you the other day．
— Forget it． I was a bit out of control myself．
A． shouldn't B． mustn't C． couldn't D． mightn't
