I’ve ______ the house since I moved here. [ ]
A. lived
B. bought
C. sold
D. had
答案:D
某同学在没有电流表的情况下,利用电压表和已知阻值的定值电阻R0,测量未知电阻Rx阻值,图所示中无法实现测量Rx阻值的电路图是
装油为什么要接地?采用什么形式接地?接地电阻是多少?如何防止静电产生?