第3题: [多项选择]断路器失灵保护动作时间,( )整定原则是正确的。 A. 对于一个半断路器接线,应瞬时再次动作于本断路器跳闸,经一时限动作于断开其他相邻断路器; B. 对于一个半断路器接线,应瞬时动作于断开其他相邻断路器; C. 对双母线(或分段单母线)接线,以无时限动作于断开与拒动断路器相关的母联或分段断路器; D. 对双母线(或分段单母线)接线,可仅经一时限动作于断开与拒动断路器连接在同一母线上的所有有源支路的断路器。 参考答案:A,D
第11题: [填空题]He (could) easily (have won) a scholarship if he (would have devoted) more time to his school work.
A. could B. have won C. would have devoted D. his school work 参考答案:C改为had devoted。 答案解析:对过去事实进行虚拟,主句用could/would have done,从句用if had done结构。