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How the First Stars in the Universe Came into
Existence Researchers believe that our universe began with the Big Bang(宇宙大爆炸)about 13 billion years ago，and that soon after that event，matter began to form as small dust grains and gases．How the first stars formed from this dust and gas has been a burning question for years，but a state of-the-art computer simulation now offers the most detailed picture yet of how these first stars in the universe came into existence． The composition of the early universe was quite different from that of today，and the physics that governed the early universe were also somewhat simpler．Dr．Naoki Yoshida and colleagues in Japan and the U．S．incorporated these conditions of the early universe，sometimes referred t A. How the Big Bang occurred about 13 billion years ago． B. How“cosmic dark ages”came into existence． C. How dust grains and gases were formed after the Big Bang． D. How the first stars came into being after the Big Bang． [单选题] 《安全生产法》的立法目的是（ ）①促进经济社会持续健康发展②保障人民群众生命和财产安全③规范生产经营单位行为④加强安全生产工作⑤防止和减少生产安全事故"
A.①②③④⑤ B.②③④⑤ C.①②④⑤ D.①②③⑤ [多项选择]城市人口中的劳动构成分为( )。
A. 劳动人口、非劳动人口 B. 基本人口、被抚养人口 C. 基本人口、非基本人口、从属人口 D. 固定人口、流动人口 E. 服务人口、基本人口 [单选题]机械维修人员必须经（ ）并（ ）后才能进行维修作业
A.站段培训取得资格 B.路局培训取得上岗证 C.相关专业培训、取得维修资格 [判断题]调车作业由调车长单一指挥。调车长应根据调车作业计划单的要求，正确、及时地显示信号，指挥调车机运行，确保行车安全。
A.正确 B.错误 [判断题]化工生产区和居民区之间、装置之间，建、构筑物之间以及设备之间应保持一定的安全距离。
A.正确 B.错误 [多选题]账页包括的内容是()。
A.账户名称 B.记账凭证的种类和号数 C.总页次和分户页次 D.摘要栏 [单项选择]Skeletal remains with animal bone blades tied to the feet testify to skating’s existence as early as 10,000 BC. These remains were found in the Netherlands. Scandinavia is called the mother of skating because of the sport’s popularity there, beginning around 1000AD. Ice skating was primarily a means of transportation at first, although documents from the Netherlands indicate that speed races were held in towns as early as the 15th century.
American athlete Jackson Haines is known as the father of modem figure skating. Haines was born in 1840 in New York City. After studying dance and ballet, he became a dancing master and applied his dancing techniques to figure skating. He performed around the world and became well known for his imaginative and artistic techniques. Haines’ s style was enthusiastically received in Europe and eventually became accepted internationally. The formation of national and international skating organizations began during the 1890s. In 1892 the Int A. History of skating. B. Development of skating. C. Skating tendencies. D. Skatin [判断题]( )冲击电压烧穿法的特点是烧穿时间较短。
A.正确 B.错误 [多项选择]运用因果分析图法对工程项目质量进行统计分析时，应注意（）。
A. 一个质量问题必须使用一张图分析 B. 应收集足够多的质量特性数据，一般不少于50个 C. 通常采用QC小组活动方式进行，以便集思广益，共同分析 D. 根据管理需要和统计目的，分类收集数据 E. 分析时要充分发表意见，层层深入，列出所有可能原因 [单选题]脚手架作业层必须设置护栏，护栏的高度为（ ）。
A.A、1.2米 B.B、1米 C.C、1.5米 D.D、无 [单项选择]男孩，3岁，因生后5个月逐渐出现智力低下，毛发颜色变浅，皮肤白皙且抽风三次来就诊。本病可能的病因是
A. 酪氨酸羟化酶缺乏 B. 苯丙氨酸羟化酶缺乏 C. 二氨喋啶还原酶缺乏 D. 过氧化酶缺乏 E. 碘化酶缺乏 [单选题]下列关于信号显示说法不正确的是( )。
A.区间设地面信号机,道岔区段设防护信号机 B.列车以车载信号为行车凭证 C.出站方向的站台侧设倒计时发车表示器 D.线路尽头设阻挡信号机 [判断题]20CP本机状态时，通过相应列车管减压和单缓指令，产生平均管压力。()
A.正确 B.错误 我来回答: 提交
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