职称英语强化练习题

[职称英语考试报考常见问题汇总]1、职称英语考试报名时间? 根据历年职称英语报考经验，网校预计职称英语考试报名时间通知将11月陆续发布，具体报名时间，请考生关注职称英语频道，届时，网校将会及时搜集整理并汇总...+阅读

职称英语强化练习题Electromagic Energy?1 White light seems to be a bination of all colors. The energy that es from a source of light is not limited to the kind of energy you can see. Heat is given off by a flame or an electric light. On a cloudy day it is possible to get a sunburn even though you feel cool. Visible light and the kinds of energy that produce warmth and sunburn are examples of electromagic energy. ?2 The sun is 93 million miles from the earth. Yet we can use energy from the sun because electromagic energy trels through space. ?3 Many other kinds of energy are also types of electromagic energy. Radio, television, and radar signals trel from transmitters to receivers as low?energy electromagic wes. Infrared(红外线的) radiation is an electromagic we. When it is absorbed by matter, heat is produced. Wes of infrared and visible light he more energy than wes of radio, television, or radar. Ultriolet rays(紫外线) and X rays are electromagic wes with even greater amounts of energy. Infrared radiation is used in cooking food and heating buildings. Sunlight and electric lights are part of our requirements for normal living. Ultriolet radiation is useful in killing certain disease anisms. X rays and gamma rays he so much energy that they trel right through solid objects. They can be used to detect and treat cancer. X rays are used in industry to find hidden cracks in metal, and in medicine to reveal broken bones. ?4 Usually we use electricity to generate electromagic energy. The source of most of our energy is the sun. Heat from the sun causes water to evaporate. When the water falls to the earth as rain, some of it is trapped behind dams and then used to operate electric generators. Other generators are powered by coal, but the energy stored in coal came from the sun, too.5 Until recently, the source of the tremendous amount of energy given off by the sun was a puzzle. If the sun depended on chemical reactions, it would he used up all its energy long ago. Experiments with electromagic radiation led to the theory that mass can be converted into energy. About forty years after the theory was proposed, nuclear energy was harnessed(利用) by man. Chemical energy es from electron(电子) rearrangement. Nuclear energy es from a change in the nucleus of an atom. pared with chemical reactions, nuclear reactions release millions of times more energy per pound of fuel. We now believe that the sun?s energy es from the nuclear reactions in which hydrogen is changed into helium(氦). ?6 Nuclear energy is beginning to pete with coal as an economical source of power to generate electricity. It is also being used to operate engines in large ships. Scientists continue to seek new and better methods of obtaining and using energy. ?1 Paragraph 3 ?2 Paragraph 4 ?3 Paragraph 5 ?4 Paragraph 6 ?