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【简答题】
Traffic lights are very important to us. I think everyone knows this. But how were they born? Do you know? Garrett A. Morgan was the father of traffic lights. He was an American. Morgan was born in 1875. His family was very poor. He left school at the age of 14. He was very clever. He always looked for better ways to do things. And he liked to make new things. At that time, every American wanted to have a car. Streets were full of cars. The traffic was not good. "Why not put three lights at each street crossing? They should be red, yellow and green, "Morgan said, "let them tell cars to go or stop. "So he made a timer (定时器) to change the lights. Now we have traffic lights on the street.
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参考答案:
举一反三
【单选题】在下列组织中含铁量最多的是:
A.
血红蛋白
B.
肌红蛋白
C.
骨髓铁
D.
易变池铁
E.
转铁蛋白
【简答题】砌体墙的细部构造包括( )、( )、( )等构造。
【简答题】【背景资料】 某单位承接某压缩气体厂房,主要为管道和设备安装。该单位项目部编制了施工组织设计和相应的施工方案,并对特殊作业人员提出了要求。施工过程检查发现,有一名正在进行压力管道氩弧焊作业的焊工甲,只有压力容器手工电弧焊合格证,另一名焊工乙有特种设备焊接作业证,因工作安排变动,已离开岗位4个月刚开始上班;一名具有起重作业证书的起重工丙,因病休假7个月刚开始上班,项目经理安排其负责设备吊装作业。 【...
【多选题】以下哪些命令可以用来关闭Linux操作系统()。
A.
shutdown
B.
halt
C.
init
D.
reboot
【多选题】砌体墙的细部构造包括勒脚、散水、明沟、构造柱、圈梁、门窗过梁、窗台、窗套、腰线和变形缝等。其中 和 为抗震构造。
A.
构造柱
B.
圈梁
【单选题】五输穴中以所溜为
A.
B.
C.
D.
E.
【单选题】墙体的细部构造不包括( )。
A.
勒脚
B.
过粱
C.
圈梁
D.
楼梯梁
【简答题】手工电弧焊时的电弧电压主要是由( )来决定的。
【多选题】桑寄生的功效是( )
A.
祛风湿
B.
益肝肾
C.
强筋骨
D.
安胎
E.
利水
【单选题】骨骼肌细胞膜内外Na+和K+浓度比较,正确的是(2005)( )
A.
细胞内Na+高,细胞外K+高
B.
细胞内Na+低,细胞外K+低
C.
细胞内Na+低,细胞外K+高
D.
细胞内Na+高,细胞外K+低
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