综合类A级模拟题：概括大意Electromagnetic
White light seems to be a combination of all colors. The energy that comes 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 kind of energy that produce warmth and sunburn are examples of electromagnetic energy.
The sun is 93 million miles from the earth. Yet we can use energy from the sun because electromagnetic energy travels through space.
Many other kinds of energy are also types of electromagnetic energy. Radio， television， and radar signals travel from transmitters to receivers as low-energy electromagnetic waves. Infrared (红外线的) radiation is an electromagnetic wave. When it is absorbed by matter， heat is produced. Waves of infrared and visible light have more energy than waves of radio， television， or radar. Ultraviolet rays (紫外线) and X-rays are electromagnetic waves 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. Ultraviolet radiation is useful in killing certain disease organisms. X-rays and gamma rays have so mush energy that they travel 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. Usually we use electricity to generate electromagnetic 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.
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 have used up all its energy long ago. Experiments with electromagnetic 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 comes from electron (电子) rearrangement. Nuclear energy comes from a change in the nucleus of an atom. Compared with chemical reactions， nuclear reactions release millions of times more energy per pound of fuel. We now believe that the suns energy comes from the nuclear reactions in which hydrogen is changed into helium (氦).
Nuclear energy is beginning to compete 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____A. Nuclear reactions as the lasting source of the suns energy
B. The most important source of energy
2. Paragraph 4____ C. Types of electromagnetic energy
D. The machines used for energy generation
3. Paragraph 5____ E. Seeking new sources of energy
F. The use of ultraviolet radiation in medicine
4. Paragraph 6 ____
5. One can get a sunburn even _____________.
6. Infrared radiation can produce heat _____________.
7. X-rays and gamma rays can be used to detect and treat cancer _____________.
8. Chemical energy is generated _____________.
A. when it is absorbed by matter
B. when it is cloudy
C. because they can pass through solid objects
D. when the sunrays are fierce
E. when a change in the nucleus of an atom takes place
F. when electron rearrangement takes place
参考答案：
1.C.该段中出现了电磁能的具体例子，所以C是答案。
2.B.the sun是该段的核心词，所以初步判定A是答案，但该段并没有提到A中说的“核反应”，所以排除A，借助该段中的第2句(The source of most of our energy is the sun./我们最重要的能源是太阳)，判定答案为B.
3.A.该段落“核反应，核能”反复出现，对比被选项选择A，而该段最后一句的句意确认A.
4.E.对比剩下被选项中的核心词(D：machine，E: new course of energy，F: ultraviolet radiation)与该段中的用词，可以直接确认答案为E.
5.B. 借助问题句中的特征词sunburn作为答案线索词， 在文章第一段的第4句找到答案相关句(On a cloudy day it is possible to get a sunburn even though you feel cool.)，判断答案为B.
6.A.该题可直接借助搭配句意判断答案。也可借助原文(利用问题句中的infrared， heat作为答案线索词)， 在第3段第4句找到答案相关句：Infrared (红外线的) radiation is an electromagnetic wave. When it is absorbed by matter， heat is produced.
7.C.可借助搭配句意直接确认答案C.也可借助原文(X-rays， gamma rays作为答案线索词)，在第3段倒数第3句找到答案相关句：X-rays and gamma rays have so mush energy that they travel right through solid objects. They can be used to detect and treat cancer.
8.F.借助问题句中的特征词chemical energy作为答案线索词， 在第5段倒数第4句找到答案相关句(Chemical energy comes from electron (电子) rearrangement. )，确认答案为F.