三相电源中相线与相线之间的电压称为()。
A、相电压
B、线电压
C、端电压
D、是相电压也是线电压
参考答案:B
I don’t know if he tomorrow. But if he , I’ll tell you.
A.will come;will come
B.comes;comes
C.will come;comes
D.comes;will come
影响物料与受热面换热的因素有哪些?