下面针对直流电动机改变电枢电压调速的特点正确的是() A.实现无级调速困难 B.调速 发布时间:2019-01-27 19:32 │ 来源:www.tikuol.com 题型:单项选择题 问题: 下面针对直流电动机改变电枢电压调速的特点正确的是()A.实现无级调速困难B.调速范围小C.机械特性硬度不变D.启动时要用启动设备
题型:单项选择题 脱疽的主要病因病理是()A.脾气不健,肝肾不足,寒湿侵袭,凝滞脉络B.湿热蕴结,寒湿外侵,气血瘀滞,脉络滞塞C.湿热下注,气血壅滞,经络阻隔,脉络瘀滞D.肝肾不足,气血两亏,络脉闭阻,筋骨失养E.情志郁结,气滞血瘀,脉络闭阻,筋脉失养 查看答案
题型:单项选择题 — What did Jack ask you just now? — He wanted to know how long _____ when I reached the cinema. [ ]A. had the film been on B. the film had startedC. the film had lasted D. had the film ended 查看答案
题型:单项选择题 中国有句古语“尧为匹夫,不能治三人;纣为帝王,足以乱天下。”从政治生活上看这最能说明()。A.权力需要制约和监督B.权力是把双刃剑C.要发挥民主对权力的制约D.要发挥法制对权力的制约 查看答案