【判断题】(............)单极二线漏电断路器上有“N”标志,表示此接线端接零线即黑线。
【单选题】选用漏电保护器,应满足保护范围内线路、用电设备相(线)数要求。保护三相线路和设备时,可选用( ).
【单选题】In paragraph 5, what does the author imply in the statement "psychology need not always be destiny?"
A.
Drivers want to reach their destinations quickly.
B.
It is possible to change the way people drive without changing how they think.
C.
Rules were changed to accommodate the knowledge that it is human nature to be distracted by car accidents.
D.
In the end, there will always be traffic jams, accidents, and other troubling events.
【单选题】如图所示,电路的三根导线中,有一根是断的,电源、电阻器R1、R2及另两根导线都是好的,为了查出断导线,某同学想先将万用表的红表笔接在电源的正极a,再将黑表笔分别连接在电阻器R1的b端和R2的c端,并观察万用表指针的示数。问万用表应调在哪档,符合操作规程?( )
【简答题】已知: y= 3x-2 - 2-3x +3 ,则(-x) y =______.
【简答题】I/O软件通常被组织( 1 )、( 2 )、( 3 )和( 4 )四个层次。
【单选题】在三相四线式380V电源供电的电气设备或者单相设备与三相设备共用的电路,应选择()漏电保护装置.
【单选题】( )说:“凡治事,公则权势,私则情谊。”
【单选题】在动力照明混合用的供电线适中,应选用()漏电保护器