【单选题】关于自耦变压器,下列说法错误的是()。
A.
自耦变压器可作升压变压器用,也可作为降压变压器用。
D.
自耦变压器工作时磁路、电路各自独立,互不关联。
【单选题】My sister wrote me to make _____.
【单选题】I wrote emails to my sister and brother last week. To my disappointment,_______of them wrote me b
A.
30.I wrote emails to my sister and brother last week. To my disappointment,_______of them wrote me back. A.either
【单选题】My roommate wrote that letter ______ me. I couldn't do it because I sprained my wrist while playing volleyball.
【单选题】-Haven’t you heard from your sister? -____________ She wrote a letter to me last week.
【简答题】空气中的电场强度 V/m ,则位移电流密度 = 。
【简答题】空气中的电场强度 V/m ,则位移电流密度Jd = 。
【简答题】弧菌科细菌和肠杆菌科细菌鉴别主要依靠——试验
【单选题】下列哪个属性不是构成 CSS 盒子模型的属性()。 Which of the following properties is not the property that makes up the CSS box model?( )
【单选题】下列关于灯丝变压器的说法,错误的是
C.
初级线圈工作电流较大,所用的导线比次级线圈直径粗
D.
灯丝加热变压器指的是给 X 线管提供灯丝加热电压的变压器