There are days in a week. The day is Saturday.
A:seven; seven
B:seven; sixth
C:seventh; seven
D:seven; seventh
如图所示的电路中,电源电动势为6V,当开关S接通后,灯泡L1和L2都不亮,用电压表测得各部分电压是Uab=6V,Uad=0,Ucd=6V,由此可判定( )