When he came out of ___ office building where he worked, the man found ___ ring lying on the ground.[ ]

A. a; a                    

B. a; the            

C. the ;the        

D. the ; a

联结心脏搏动和肺司呼吸之间的中心环节是哪一项

A．元气
B．宗气
C．清气
D．营气
E．卫气