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Paula: Seems colder today,_________ ？
Peter: It is colder. It was on the weather forecast.
Paula: Was it？ I'm sure it's not normally this cold at this time of year.
A． or is it just me
B． or is it just for me
C． or only I felt it
D． or just I'm feeling it
答案
更多“Paula: Seems colder today,_________？Peter: It is colder. It was on the weather fo”相关的问题
第1题
More than 40 years passed before physicists were able to offer an explanation for superconductivity. The accepted theory, developed in the 1950s, holds that the fundamental behavior. of electrons changes at very low temperatures because of the effects of quantum mechanics. Electrons are tiny particles that make up the outer part of an atom, circling rapidly around the nucleus of the atom. In a regular conductor—a metal that conducts an electric current—the outermost electrons are not bound tightly to the atoms, and so they move around relatively freely. The flow of these electrons is an electric current.
At normal temperatures, a conductor's electrons cannot move completely freely through the metal because they are "bumped around" by the metal's atoms. But according to the leading theory of superconductivity, when a metal is very cold, electrons form. pairs. Then, like couples maneuvering on a crowded dance floor but never colliding, the paired electrons are able to move unimpeded through the metal. In pairing up, it seems, the electrons are able to "blend together" and move in unison without resistance. This explanation seems to account for superconductivity at extremely low temperatures, but in 1986 scientists in Switzerland found that some metal-containing ceramics are superconductors at much higher temperatures. By 1992, scientists had developed ceramics that become superconducting at - 297'F, and some researchers speculated that room-temperature superconductors may be possible. Scientists are still trying to formulate a theory for high-temperature superconductivity.
The new ceramic materials can be maintained at their superconducting temperatures, with relatively inexpensive liquid nitrogen rather than the much colder and much more costly liquid helium required by metal superconductors. The cost difference could make superconductivity practical for many new technologies. For example, magnetically levitated trains, which require superconducting electromagnets, would be much cheaper to build than they are now. Superconducting devices might also be used for advanced power transmission lines and in new types of compact, ultrafast computers. But for the time being, superconductivity is finding application mostly in scientific research and in some kinds of medical imaging devices.
The flow of an electric current in a regular conductor is made possible by the fact that______.
A．electrons circle rapidly around the atom
B．the outermost electron move relatively freely around the atom
C．the innermost electrons stick to the atom
D．the outermost electrons are bound tightly to the inner ones
第2题
Paula: Hello, my name is Paula Field. Welcome you to Tectron UK.
Jens: Thank you. _________.
A． Nice to meet you
B． It was kind of you
C． You've got a nice name
D． Nice meeting you
第4题
Why is Paula unhappy？
A．The apartment is too far from the campus.
B．The apartment needs a lot of repair work.
C．She's having trouble with the owner of the apartment.
D．Her roommate won't share expenses.
第5题
Prehistoric (史前的）had little choice in what he ate. He ate what he could find: roots, eggs, fruits and the meat of smallanimals. Early man had no way to control his food supply. If there was no rain, or the weather was too hot or too cold,plants would not grow, and he would have little or no food. When he ate all the food in one place, he had to move to anotherregion for food.
Man’s life changed when he learned to grow plants and to raise animals. He also learned to use fire to prepare his food. Later, he learned to make tools and weapons, and to make containers to store his food. Man could now live in one place andproduce his own food. So civilization (文明）began. Great civilizations slowly developed in regions where food wasplentiful — along the Nile River in Egypt, and by the Yellow River in China.
The kinds of plants which are raised by man are different in each geographical region. In the colder regions very fewplants can be grown; in the warmer parts of the world great varieties of plants are found. In Asia, rice has become the mostimportant crop. In North America, the most important grains are wheat and com. In Europe and North Africa, wheat is themain crop. In the tropical (热带的）regions of the world，many kinds of fruit grow naturally or arc planted by man.
With the development of methods of keeping food fresh, it became possible to send most food products from one partof the world to another. Today foods are kept fresh in many ways and sent all over the world. Man no longer depends on thefood he grows in his own area only.
As man has learned more about plants and animals, the production of food has become a more technical process. In thefuture, it seems possible that vast quantities of food may come from the ocean. Food may also be produced in new ways.
According to the first paragraph.man has to ensure________
A.the amount of food he needs
B.the quality of the food he needs
C.the quality of his lifeon theearth
D.the number of people livingon the earth
If the weather was extremely bad, early man would？A.raise new crops
B.suffer from hunger
C.raise small animals
D.suffer from diseases
From Paragraph 3 we know that civilizations developed in areas？A.where the weather was good
B.where there was enough rain
C.where there was a large amountof food
D.where there were a great numberof animals
Which of the following is true according to Paragraph 4？A.There are few plants in colder regions.
B.Corn is the most important crop in Asia.
C.There are few plants in hotter regions.
D.Rice is the main crop in Europe.
As man’s knowledge about plants and animals increases,.A.fewer plants will be needed
B.fewer animals will he available
C.more and more land will be
D.more and more food will he available
请帮忙给出每个问题的正确答案和分析，谢谢！
第7题
The deeper divers goes down in the sea,
A.the wanner the sea becomes
B.the colder they find the sea is
C.the less the water above presses down
D.the heavier their clothes must be
第8题
If there were no greenhouse effect，________．
A.earth would be thirty degrees colder
B.all of the above answers are correct
C.man could not live on the earth
D.no plants would grow oil oui planet
第9题
A.As it seems improbable
B.As improbable it seems
C.Improbable as it seems
D.Improbable as seem it
第10题
The author seems to regard Greenspan's manipulation of interest rates with
A．disapproval.
B．doubt.
C．approval.
D．admiration.
