【多选题】相比于传统汽车,纯电动汽车的优点有哪些?
【单选题】A cosmetics company has two production cost centres (X and Y) and two service cost centres (V and W). the following overheads have been apportioned and allocated to the four cost centres. Cost centre ...
【单选题】一台转子 出现断 路的三相异步电动机,若给其定子绕组通入三相交流电源,则( )。
B.
定子中 不会产生旋转磁场, 因而 电 动机不会启动
C.
定子中 会产生旋转磁场,但 转子导体不会切割磁力线,也不会产生感应电动势
D.
定子绕组 产生旋转磁场, 转子导体切割磁力线 产生感应电动势,但由于转子断路而不会产生感应电流,更不会 产生电磁转矩, 因而电 动机无法启动
【简答题】听力原文:W: OK John, how much would you ask for this coffee and tea set? M: Well, ordina61y a coffee set is $30 and a tea set $20. W: But our business relation ship is of long standing. Can you give me a ...