A:醋酸菌、酵母菌
B:酵母菌、毛霉
C:醋酸菌、乳酸菌
D:酵母菌、醋酸菌
如图所示,电源电压U=10V,定值电阻R=20Ω,闭合开关S,电压表的示数是6V,通过小灯泡的电流是( )
With nothing ________ to burn, the fire became weak and finally died out.