第5题: [单项选择]As early as 1647 Ohio made a decision that free, tax-supported schools must be established in every town ______ 50 households or more. A. having B. to have C. to have had D. having had 参考答案:A 答案解析:现在分词having作后置定语,修饰前面的名词every town,因此选A。
第19题: [单项选择]电压互感器电压及电缆截面选择。 电测量用电压互感器二次回路电缆截面的选择,应使电力系统内部的0.5级电能表电缆的电压降不大于额定二次电压的( )。 A. 0.2%; B. 0.25%; C. 0.5%; D. 1%。 参考答案:C 答案解析:[解析] 依据DL/T 5137-2001第11.2.1条要求。