A:hamburger
B:cake
已知:x=2+ 2 ,y=2﹣ 2 .
通过甲乙两个电阻的电流随其两端电压的关系如图所示,把这两只电阻串联起来接在电源两端,通过它们的电流是0.4A,则电路的总功率是____ W.
We stopped _________, but there was not any sound.