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[不定项选择题]共用题干 Learn About Light

1 Ancient civilizations were amazed by the existence of light for thousands of years?The Greek philoso-
phrrs believed that light was made up of countless,tiny particles that enter the human eye and create what
we call vision.However,Empedocles and a Dutch scientist named Christian Huygens believed that light wag
like a wave.According to them,light spread out and travelled like a straight line.This theory was accepted
during the 19th century.
2 In 1905,Albert Einstein published a research paper in which he explained what is referred to as the
photoelectric effect.This theory explains that particles make up light.The particles Einstein was referring to
are weightless bundles（束）of electromagnetic（电磁）energy called photons（光子）.Today,scientists agree
that light has a dual（二重）nature一it is part particle and part wave. It is a form of energy that allows us to
see things around us.
3 Things that give off light are known as sources of light.During the day,the primary source of light is
the sun.Other sources of light include stars,flames,flashllights,street lamps and glowing gases in glass
tube.
4 When we draw the way light travels we always use straight lines.This is because normally light rays
travel in a straight line.However,there are some instances that can change the path and even the nature of
light. They are reflection,absorption,interference（干扰）,etc.
5 Physicists have attempted to measure the speed of light since the early times.In 1849,Hippolyte
Fizeau conducted an experiment by directing a beam of light to a mirror located kilometers away and placed
a rotating cogwheel（旋转齿轮）between the beam and the mirror. From the rate of rotation of the wheel,
number of wheel'S teeth and distance of the mirror,he was able to calculate that the speed of light is 313
million meters per second.In a vacuum（真空）,however,the speed of light is 299,792,458 meters per
second.This is about a million times faster than the speed of an airplane. Paragraph 5 _______
A.How is the Nature of Light Explained Today?
B.What are Sources of Light?
C.How did Physicists Measure the Speed of Light?
D.How does Light Travel?
E.How did People Think of Light Years Ago?
F.What Causes a Shadow?

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[单项选择]酪氨酸在体内可以转变成（）。
A. 苯丙氨酸
B. 肾上腺素
C. 犬尿酸
D. 甲状旁腺素
E. 5-羟色胺

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[判断题]保持队列整齐，出列、应当报告并经允许
A.正确
B.错误

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[单项选择]阴虚血热，冲任不固的崩漏、月经过多，宜首选（）
A. 龟甲
B. 鳖甲
C. 石斛
D. 天冬
E. 麦冬

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[单项选择]抑制剂在循环气系统中（）。
A. 只抑制副反应
B. 只抑制主反应
C. 既抑制副反应也抑制主反应
D. 既不抑制副反应也不抑制主反应

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[单选题]CRRT患者局部枸橼酸钠抗凝过程中，需监测滤器后的血气及离子钙浓度，一般滤器后的钙离子浓度维持在多少（）
A.0.1—0.2mmol/L
B.0.2—0.3mmol/L
C.0.2—0.4mmol/L
D.0.4—0.6mmol/L
E.0.5—0.7mmol/L

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[单选题]根据《危险化学品安全管理条例》，新建、改建、扩建生产、储存危险化学品的建设项目，应当由（）进行安全条件审查。
A.企业
B.需求单位
C.企业负责人
D.安监部门

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[判断题] 全面依法治国是国家治理的一场深刻革命,必须坚持厉行法治,推进科学立法、严格执法、公正司法、全民守法。()
A.正确
B.错误

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[单项选择]对牛进行尸检时，应采取的姿势是（）
A. 仰卧式
B. 俯卧式
C. 左侧卧
D. 右侧卧
E. 倒挂

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[多项选择]Which of the following is true about the following share access properties？（）
A. +managers will be resolved as a Winbind group.
B. The timo and taki users can manipulate files regardless of the file system permissions.
C. +managers will be resolved as a Unix group.
D. +managers is a builtin default Samba group.
E. The "admin users" can be applied only to print shares.

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[判断题]自动呼吸复苏器主要对丧失自主呼吸能力的伤员进行供氧。
A.正确
B.错误

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[单项选择]It can be safely concluded from the text that smaller members of the Euro area would become more
A. vocal in their own interests.
B. angry in face of potential threats.
C. considerate of large members.
D. supportive of a proposed treaty.

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