目前国际上通用的物流条码制有（）A.ITF-14条码 B.EAN-13码 C.ITF

Nuclear power’s danger to health, safety, and even life itself can be summed up in one word: radiation.

Nuclear radiation has a certain mystery about it, partly because it cannot be detected by human senses. It can’t be seen or heard, or touched or tasted, even though it may be all around us. There are other things like that. For example, radio waves are all around us but we can’t detect them, sense them, without a radio receiver. Similarly, we can’t sense radio activity without a radiation detector. But unlike common radio waves, nuclear radiation is not harmless to human beings and other living things.

At very high levels, radiation can kill an animal or human being outright by killing masses of cells in vital organs. But even the lowest levels can do serious damage. There is no level of radiation that is completely safe. If the radiation does not hit anything important, the damage may not be significant. This is the case when only a few cells are hit. And if they are killed outright, your body will replace the dead cells with healthy ones. But if the few cells are only damaged, and if they reproduce themselves, you may be in trouble. They reproduce themselves in a deformed way. They can grow into cancer. Sometimes this does not show up for many years.

This is another reason for some of the mystery about nuclear radiation. Serious damage can be done without the victim being aware at the time that damage has occurred. A person can he irradiated and feel fine, then die of cancer five, ten, or twenty years later as a result. Or a child can be born weak or liable to serious illness as a result of radiation absorbed by its grandparents.

Radiation can hurt us. We must know the truth.

The word "significant" in Paragraph 3 most probably means（）

A. responsible

B. meaningful

C. fatal

D. harmful

2009年,在诺贝尔奖各奖项即将揭晓之际，诺贝尔基金会评出了诺贝尔奖百余年历史上 “最受尊崇的”三位获奖者。其中之一是1921年物理学奖得主阿尔伯特爱因斯坦。爱因斯坦是一名人道主义者、和平主义者，也是一位伟大的科学家。“爱因斯坦是一个造物者！”，这是著名华裔物理学家诺贝尔奖得主杨振宁对爱因斯坦的评价。杨振宁在这里高度评价爱因斯坦，主要依据是他（  ）

A．否定牛顿力学体系

B．创立现代物理学

C．改变了人们的思维模式

D．发现和创造了相对论

通过实验装置的改进，可培养创新精神。下图是经小明同学改进后制取和检验二氧化碳性质的实验简图。

(1)实验现象是接近三通管下口的火柴火焰熄灭，而接近三通管上口的火柴仍在燃烧。由此可判断二氧化碳具有的性质有：①物理性质________________；②化学性质__________________。

(2)有两瓶无色气体，它们分别是O₂和CO₂，你如何通过简单的实验将它们区别开来？（简述操作和分析过程）

A lot of e-mail English words come _____ a computer program _____ ICQ.    [ ]

A. from; call

B. out of; call

C. from; called

D. to; call

信息加工学习理论认为学生的学习是一个信息加工的过程。信息是经（）形式储存在长时记忆中。