职称英语 2021_09_24 每日一练


Henry cannot resist the lure of drugs.

A.abuse

B.flavor

C.temptation

D.consumption

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Do scientists know how many cryptic species exist?

A.Not yet.

B.Yes, they do.

C.They will know the answer in another one or two years.

D.They will never know the answer.

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And the cars are tested for defects before leaving the factory.

A.functions

B.faults

C.motions

D.parts

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Electromagnetic Energy

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 sun's 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.

A. Nuclear Reactions as the Lasting Source of the Sun's Energy

B. The Most Important Source of Energy

C. Types of Electromagnetic Energy

D. X-rays Are Used to Detect and Treat Cancer.

E. Seeking New Sources of Energy

F. Nuclear Energy is Beginning to Compete with Coal

Paragraph 3 ______

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Defending the Theory of Evolution Still Seems Needed

Judith S. Weis, a biology professor who serves as president of the American Institute of Biological Sciences (AIBS) is leading a nationwide effort to "defend" the theory of evolution. Weis leads the effort in the face of what the institute views as opposition and indifference from school boards and government entities.

The Institute believes that the teaching of evolution in America is being diminished by the teaching of creationism as well as by an overall lack of teaching Darwin's theory in high school. "There's nothing that requires schools to teach evolution. Sometimes teachers in high schools just leave it out. However from the point of view of biologists, evolution is the central theory of biology upon which everything is based," said Weis. "Unfortunately, teaching evolution has become a political issue in many parts of the country and AIBS, as a representative of biologists, wanted to be a major force speaking out in favor of its teaching. "

Weis said the institute is working together with the American Geological Institute and the National Association of Biology Teachers and its 80-plus member organizations to address" the political and legislative threats to teaching evolution. In states challenging its teaching, the institute responds by sending letters to school boards and state legislatures, by providing testimony at public meetings and by notifying members and affiliated organizations. AIBS, with more than 80 member societies and 250,000 members, has established an email system enabling scientists and teachers in each state, and member societies, to keep each other informed about threats to the teaching of evolution.

Darwin's theory of evolution holds that living things change and adapt to their environment and that present-day species ( including human beings) are descended from earlier species through modification by natural selection. The theory has been accepted by scientists for nearly 100 years, Weis said, and has been refined, extended and strengthened over the years by findings in paleontology and developmental biology. Discoveries in genetics, molecular biology and genomics—all of which provide significant benefits for human health—would not be possible without the underlying knowledge of evolution. And, Weis adds, "modem molecular biology and genomics have increased our understanding of how evolution works." Nonetheless, evolution remains a politically, if not scientifically, controversial issue.

Weis said that this year alone, seven states have had either local or statewide efforts to water down the teaching of evolution, or "balance" it with the teaching of creationism—a religious belief that different species were created separately by a higher power, such as God. "Rarely does anyone now use the word ' creationism, ' because that's too obvious," Weis said. "The current terminology is ' intelligent design. ' "

According to the first paragraph, which of the following statements about the theory or evolution is true?

A.Government entities support AIBS's effort to defend the theory of evolution.

B.School boards oppose AIBS's effort to defend the theory of evolution.

C.AIBS and school boards advocate the teaching of the theory of evolution.

D.The theory of evolution and that of creationism co-exist peacefully in schools.

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What was scientists' understanding of cryptic species?

A.They occurred in equal numbers in all biogeographical regions.

B.They were mostly found in insects and reptiles.

C.They were likely to be in tropical rather than temperate regions.

D.Both B and C.

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