【单选题】投服中心持有所有在上海证券交易所和深圳证券交易所上市的公司每家()A股股票。
【单选题】The scientist _____ that there would be a rainstorm the next week and it did happen. [ ]
【单选题】Although Albert Einstein would someday be _________ famous scientist, he did not like __________ school.
【单选题】载波频率对电动机的电流影响较大,为得到较为理想的正弦电流曲线,应将载波频率设置为:( )
【单选题】对厂用一类负荷的供电方式是( )
B.
应由两个电源进行供电,备用电源采用手动切换方式投入
C.
应由两个电源供电,一个电源消失后另一个电源自动投入