单项选择题
A．important B．unimportant C．somewhat important D．very important
A．the passing of information and making of the decisions B．the meeting and hitting back of the bail C．the coordinated movements of our eyes, brain and muscles D．a lot of practice before playing tennis
A．the birth rates will go up B．the birth rates will stop going down C．the opportunities for getting jobs will go up D．both the birth rates and the opportunities for getting jobs will go up