【单选题】Please choose the correct name for the following cloud (in the middle part in the figure).
【判断题】七穆指即郑七穆,是春秋时期郑国七家卿大夫家族的合称,包括驷氏、罕氏、国氏、良氏、印氏、游氏、丰氏。
【单选题】对称正弦三相电压源星形联接,若相电压 u A =100 sin( ω t- 60 ° )V ,则线电压 u AB = ( ) V 。
【单选题】In the roof, the main ridge is raised in the middle part and vertical ridges are added to both ends of the raised part.