问题
选择题
—Could I use your phone for a moment?
— ______. Help yourself. [ ]
A. Take your time
B. Forget it
C. By all means
D. Never mind
答案
答案：C
搜题请搜索小程序“爱下问搜题”
—Could I use your phone for a moment?
— ______. Help yourself. [ ]
A. Take your time
B. Forget it
C. By all means
D. Never mind
答案：C
，超导临界电流
，限流电阻
，小灯泡L1、L2都标有“6V，6W"的字样，电源的电动势E=8V，内阻r=2
。原来小灯泡Ll正常发光。若小灯泡Ll突然发生短路，则 