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问题 单项选择题

下列施工措施中不能降低混凝土入仓温度的是( )

A．合理安排浇筑时间
B．采用薄层浇筑
C．对骨料进行预冷
D．采用加冰或加冰水拌合

答案

参考答案：B

解析： 降低混凝土的入仓温度：合理安排浇筑时间；采用加冰或加冰水拌合；对骨料进行预冷。

阅读理解

阅读下列短文，选择正确答案。

     Peter and I are good friends. Peter is an American boy. I am a Japanese girl. He is thirteen. I am

twelve. We are in the same class,Class Two.

     Peter has a nice clock. He likes it very much. He puts it on his desk. Every morning it wakes him

up(叫醒他). I have a new watch. It looks beautiful. I wear(戴)it everyday. It tells me the time. It helps

(帮助)me a lot in my daily life. I can not live without it. 

1. Peter and I are _____. 

A. friends      

B. teachers      

C. sisters      

D. brothers

2. Peter is _____. 

A. an English boy                

B. a Japanese girl    

C. an American boy              

D. an English girl

3. I have _____. 

A. a beautiful clock              

B. an old watch    

C. a new watch                  

D. a nice clock

4. Peter _____. 

A. wears his clock everyday        

B. puts his clock on his desk

C. wears his new watch every day  

D. likes his new watch very much

5. Peter and I are_____.   

A．in different classes            

B．in the same row    

C．in Class Two                  

D．in America
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问答题


错接插座电源线造成的触电死亡
某工业公司在海滨城市新建一所干部培训中心，已基本竣工，为迎接当天省城来的领导验收检查，培训中心管理人员决定尽快将领导住的房间内的淋浴设备安装好。于是安排水暖工×××去安装电加热淋浴器。×××安装好淋浴器后，用插头接通电源，正在打开热水阀门时，手推阀门，惨叫一声，跪倒在地上。这时正在房间内整理卧具的两名服务员听到叫声，来到卫生间一看，×××跪倒在地上，手握铁管。一边询问他怎么了，一边上前去扶他，谁知刚一接触他的身体，感到麻电，慌忙去喊人，切断电源，将水暖工送至医院，抢救无效而死亡。
主要原因分析：现场试验分析，加热器的外壳和水管都带电，对地电压为相对地电压。进一步检查发现，墙上的单相三级电源插座中的接地极(有标志)带电。接地极带电的原因是电工接线时，将相线直接接到接地极上。所以当加热器的三极插头一接上电后，与加热器的外壳连接的整个金属管道都带电，加上卫生间地面积水，环境恶劣，水暖工握住阀门后无法自主摆脱，造成其触电死亡。

请分析这起事故发生的原因。
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