【单选题】
在一般场所,为保证使用安全,应选用___电动工具。
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【单选题】
万用表电压量程2.5v是当指针指在___位置时电压值为2.5v。
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据一些资料表明,心跳呼吸停止,在___min内进行抢救,约80%可以救活。
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继电器是一种根据___来控制电路“接通”或“断开”的一种自动电器。
A. 外界输入信号(电信号或非电信号)
B. 电信号
C. 非电信号
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当低压电气火灾发生时,首先应做的是___。
A. 迅速离开现场去报告领导
B. 迅速设法切断电源
C. 迅速用干粉或者二氧化碳灭火器灭火
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热继电器的整定电流为电动机额定电流的___%。
【单选题】
我们平时称的瓷瓶,在电工专业中称为___。
【单选题】
根据线路电压等级和用户对象,电力线路可分为配电线路和___线路。
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一般照明线路中,无电的依据是___。
A. 用摇表测量
B. 用电笔验电
C. 用电流表测量
【单选题】
“禁止攀登,高压危险!”的标志牌应制作为 ___。
A. 白底红字
B. 红底白字
C. 白底红边黑字
【单选题】
钳形电流表测量电流时,可以在___电路的情况下进行。
【单选题】
在对可能存在较高跨步电压的接地故障点进行检查时,室内不得接近故障点___m以内。
【单选题】
非自动切换电器是依靠___直接操作来进行工作的。
【单选题】
在易燃易爆场所使用的照明灯具应采用___灯具。
【单选题】
当电气设备发生接地故障,接地电流通过接地体向大地流散,若人在接地短路点周围行走,其两脚间的电位差引起的触电叫___触电。
【单选题】
建筑施工工地的用电机械设备___安装漏电保护装置。
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热继电器具有一定的___自动调节补偿功能。
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电业安全工作规程上规定,对地电压为___v及以下的设备为低压设备。
【单选题】
稳压二极管的正常工作状态是___。
A. 导通状态
B. 截至状态
C. 反向击穿状态
【单选题】
导线接头的机械强度不小于原导线机械强度的___%。
【单选题】
交流接触器的额定工作电压,是指在规定条件下,能保证电器正常工作的()电压。___
【单选题】
正确选用电器应遵循的两个基本原则是安全原则和()原则。___
【单选题】
热继电器的保护特性与电动机过载特性贴近,是为了充分发挥电机的()能力。___
【单选题】
并联电力电容器的作用是()。___
A. 降低功率因数
B. 提高功率因数 C、 维持电流
【单选题】
为了防止跨步电压对人造成伤害,要求防雷接地装置距离建筑物出入口、人行道最小距离不应小于___米。
【单选题】
PE线或PEN线上除工作接地外其他接地点的再次接地称为()接地。___
【单选题】
“禁止合闸,有人工作”的标示牌应制作为 ()。___
【单选题】
当电气设备发生接地故障,接地电流通过接地体向大地流散,若人在接地短路点周围行走,其两脚间的电位差引起的触电叫()触电。___
【单选题】
根据线路电压等级和用户对象,电力线路可分为配电线路和___线路。
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----- John， may I ask you a favour？ ----- _________
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It was the wealth of the_____pioneer landowner John Harvard that made Harvard University possible.___
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I didn't expect to receive a postcard from you！It's really _____my wildest imagination.___
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John Smith is _____ honest young man.___
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She __________ in wearing that old – fashioned hat.___
A. insists
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Some of the meat came from Canada. How about________？___
A. another
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I have brought you ___ flowers for your birthday. ___
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【单选题】
I’m busy now ,ask him to see me ____ time.___
A. the other
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【单选题】
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A. in case
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【单选题】
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A. turned off
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A. have watched
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A. little
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______you choose， make sure that it is a good one. ___
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A. according to
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Entering the room， I found my father __ at the desk and ___ something .___
A. seat... write
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【单选题】
Cake __________ of flour, sugar, egg and some other ingredients. ___
A. contained
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D. composed
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A. obtain
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A. where
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__________ the English examination I would have gone to the concert last Saturday. ___
A. But for
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A. were to can
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A. having frightened
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【单选题】
----- _______is your English teacher？ ----- The one in red. ___
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