A:therefore
B:anyhow
C:however
D:though
I usually ____ ____ them ____ the ____ at weekends.
根据如图完成下列问题:
如图所示,R1=R,R2=2R,R3=3R,Rg=4R,电源负极接地,闭合开关S稳定后,电容器带电量为Q1;断开开关S将R1和R3的位置互换,开关重新闭合稳定后,电容器带电量为Q2,则Q1和Q2的比值为( )