2. 外语
  3. A summary of the physical and chemical nature of life must begin, not on the Earth, but in the Sun; in【C1】______at the Sun’s ver

A summary of the physical and chemical nature of life must begin, not on the Earth, but in the Sun; in【C1】______at the Sun’s ver

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问题     A summary of the physical and chemical nature of life must begin, not on the Earth, but in the Sun; in【C1】______at the Sun’s very center. It is here that is to be found the【C2】______of the energy that the Sun pours out into space is【C3】______The energy takes the form of light and heat. This energy is【C4】______at the center of the Sun as billions【C5】______billions of nuclei of hydrogen atoms【C6】______with each other and fuse together to form nuclei of helium, and in doing so,【C7】______some of the energy that is【C8】______in the nuclei of atoms. The【C9】______of light and heat of the Sun【C10】______that some 600 million tons of hydrogen be【C11】______into helium(氦)in the Sun every second. This the Sun has been doing for several thousands of millions of years. The nuclear energy is released at the Sun’s center as high-energy gamma radiation,【C12】______of electromagnetic radiation like light and radio waves, only of very much shorter【C13】______. This gamma radiation is absorbed by atoms inside the Sun to be【C14】______at slightly longer  wavelengths. This radiation, in its【C15】______is absorbed and reemitted. As the energy filters through the【C16】______of the solar interior, it passes through the X-ray part of the spectrum【C17】______becoming light. At this stage, it has reached what we call the solar surface, and can escape into space without being absorbed further by solar atoms. A very small【C18】______of the Sun’s light and heat is emitted in such directions that【C19】______passing  unhindered through interplanetary space, it【C20】______the Earth.
【C13】
选项 A、pace
B、wavelength
C、frequency
D、rate
答案B
解析 名词辨义题。该处意在表明：作为电磁射线的一种，伽马射线与光波和无线电波类似，但是只是在……上略短。通过常理可判断应该是在波长上。故应选择wavelength。pace意为“步调，步法”，与射线无关；frequency意为“频率”，频率不论长短．而论快慢；rate意为“比率，等级”．亦不能用short来形容，可说small rate。
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大学英语四级

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