【单选题】The two friends _____ on the Internet for three hours, and they would go on till the next morning.
【单选题】Three Friends of Winter
【简答题】She brought with her three friends, none of I had ever met before. A. them B.who C. whom D.th...
【单选题】By 2020, scientists _____ a cure for canner.
【简答题】一台三相异步电动机,额定数据如下:U N =380V,f N =50Hz,P N =7.5kW,n N =962r/min,定子绕组为△接法,2p=6,cosψ N =0.827,p Cu1 =470W,p Fe =234W,p mech =45W,p △ =80W。试求额定负载时的:
【简答题】一台绕线式三相异步电动机的额定数据为:P N =75kW,n N =720r/min,λ N =2.4,E 2N =213V,I 2N =220A,定、转子均为Y接,该电机拖动位能性恒转矩负载,大小为T L =T N ,忽略传动机构转矩损耗,试求:
【单选题】在国际营销活动中,最严重的政治风险是( )。
【单选题】Three years ________ a long time to be cut off from contact with your friends.