提供功率的电源是?电路图如图：_ _1 1 1Us Is R1_1_1不知道能不能看懂.Us上+下-,Is上为正Us为4

鞋子上的us, 很着急,明天比赛!Doing eye exercises is good for us students,答案上说us是 如图.N为含源线性电阻网络,Us为直流电压源.当Us=0时,R消耗的功率为4W；当Us=2V时,R消耗的功率为9W,则U The book is interesting to us.转换为同义句 The book _______ us.(只填 Walking is good ( )us Everything between us is To speak English well for us is diffcult.(改为同义句)_ _ _ _ us _ those are us和this is us哪个是对的,为什么 it is nice to have you with us能不能说成 have you and us their idea is _ to all of us and you do not need to tell us us It is _ difficlt for us to climb the mountains