题目

Let’s have a rest. I was ______ tired to go on ______. A. too, walk           B. too, walking              C. so, walk                   D. enough, walking 答案：B如图，三相交流发电机每相电压为220V，接成星型，如果负载接成三角形，则负载每相的电压是 A． 220 V      B．220V    C． 220V D．因三相负载电阻大小未知，每相的电压无法判断