As some experts say, shopping by television will never take ________ place of shopping in stores,

because many people find shopping at a store is ________ great enjoyment.[ ]

A. /; a  

B. the; a

C. a; the  

D. a; /

心输出量是指

A．一次心动周期一侧心室射出的血量
B．一次心动周期两侧心室射出的血量
C．每分钟由一侧心房流入心室的血量
D．每分钟由一侧心室射出的血量
E．每分钟由左、右心室射出的血量之和