题目

— It’s too hot here. Would you mind my _________ the windows? —________. Do it as you like, please. A．to open; OK                       B．opening; Certainly not C．Closing; Of course              D．open; Good idea 答案：B如图是关于电阻R1、R2的I-U图象．由图象可知，阻值R1：R2=    ．若将这两电阻并联后接在电压为2V的电源两端，则该并联电路的干路电流是    A．