【单选题】The _____ on his face suggested that he was a little nervous. [ ]
【判断题】国际分工的深化阶段是从第一次世界大战至今。
【单选题】某交流电压u=100sin(100πt+π/4),当t=0.01s时的值是( )。
【单选题】某交流电压u=100sin(100 π t+45 ° )V ,当 t=0.01s时的值是( )。
【单选题】某交流电压u=100sin(100πt+ )V.当t=0.01 s时的值是( )。
【简答题】某一正弦交流电路的输入电压 u =100 sin ( 100π t +60° ) V ,电路中的总电流为 i = 10 sin100π t A ,则该电路消耗的有功功率 P =( ) W 。
【单选题】某交流电压u=100sin(100πt+π/4),当t=0.01s时的值是( )。
【简答题】His expression became very_________ when we told him what had happened.
【单选题】某交流电压u=100sin(100πt),当t=0.01s时的值是( )。