Lang Ping , who used to be captain of Chinese Women’s volleyball

team, ______volleyball in China for almost twenty years.

A．have played

B．played

C．was playing

D．had played

视在功率S表示（）

A、电源所做的功率

B、负载所做的功率

C、电源输出最大功率

D、负载所消耗最大功率