【单选题】It is often more economical to supply such power from ________.
【判断题】变压器空载实验分别在高压侧和低压侧施加额定电压,则测得的空载电流是相同的。
【判断题】国际上研究创造性的第一部著作是弗洛伊德的《遗传与天才》一书。
【单选题】—It's my birthday today! —_____. [ ]
C.
Happy birthday to you!
【简答题】国际上研究创造性的第一部著作是弗洛伊德的《遗传与天才》一书。()
【单选题】It is more economical to use (), because of their greater strength and longer useful lives.正确答案A