室内装饰设计员综合练习
室内装饰设计员综合练习
如何将S2126交换机的登陆密码配置为Star？（）
A:set password star B:login star C:enable secret level 10star D:enable password star
Millions of stars are travelling about in space. A few form groups which journey together, but most of them travel alone. And they travel through a universe so large that one star seldom comes near to another.
We believe, however, that some two thousand million years ago, another star wandering through space, happened to come near our sun. Just as the sun and the moon raise tides on the earth, so this star must have raised tides on the surface of the sun. But they were very different from the small tides that are raised in our oceans; a large tidal wave must have travelled over the surface of the sun, at last forming a mountain so high that we cannot imagine it. As the cause of the disturbance (动荡) came nearer, so the mountain rose higher and higher. And before the star began to move away again, its tidal pull had become so powerful that this mountain was torn to pieces and threw off small parts of itself into space. These small pieces have been going round the sun ever since. They are the planets (行星).
A:the star moved away from the sun B:another star happened to come near the sun C:the sun and the moon raised the tides on the earth D:a large tidal wave of a star travelled over the surface of the sun
Millions of stars are traveling about in space. A few form groups which journey together, but most of them travel alone. And they travel through a universe so large that one star seldom comes near to another.
We believe, however, that some two thousand million years ago, another star wandering through space, happened to come near our sun. Just as the sun and the moon raise tides on the earth, so this star must have raised tides on the surface of the sun. But they were very different from the small tides that are raised in our oceans; a large tidal wave’ must have travelled over the surface of the sun, at last forming a mountain so high that we cannot imagine it. As the cause of the disturbance (动荡) came nearer, so the mountain rose higher and higher. And before the star began to move away again, its tidal pull had become so powerful that this mountain was torn to pieces and threw off small parts of itself into space. These small pieces have been going round the sun ever since. They are the planets (行星).
Some two thousand million years ago, the mountain on the sun was raised probably because______.
A:the star moved away from the sun B:another star happened to come near the sun C:fhe sun and the moon raised the tides on the earth D:a large tidal wave of a star travelled over the surface of the sun
Black Holes
What is a black hole Well, it’s difficult to answer this question, since the terms we normally use to describe a scientific phenomenon are inadequate here, Astronomers and scientists think that a black hole is a region of space (not a thing) into which matter has fallen and from which nothing can escape—not even light. So we can’t see a black hole. A black hole exerts (施加) a strong gravitational (重力的) pull and yet it has no matter. It is only space—or so we think. How can this happen
The theory is that some stars explode when their density increases to a particular point; they "collapse" and sometimes a supernova (超新星) occurs. The collapse of a star may produce a "White Dwarf (白矮星) "or a "neutron star"—a star whose matter is so dense that it continually shrinks by the force of its own gravity. But if the star is very large this process of shrinking may be so intense that a black hole results. Imagine the earth reduced to the size of a marble, but still having the same mass and a stronger gravitational pull, and you have some idea of the force of a black hole. Any matter near the black hole Is sucked in. It is impossible to say what happens Inside a black hole.
Our space and time laws don’t seem to apply to objects in the area of a black hole. Einstein’s relativity theory is the only one that can explain such phenomena. Einstein claimed that matter and energy are interchangeable, so that there is no "absolute" time and space, There are no constants at all, and measurements of time and space depend on the position of the observer— they are relative. Einstein’s theory provided a basis for the idea of black holes before astronomers started to find some evidence for their existence. It is only recently that astronomers have begun specific research into black holes.
The most convincing evidence of black holes comes from research into binary (由两部分组成的) star systems. In some binary star systems, astronomers have shown that there is an invisible companion star, a "partner" to the one which we can see in the sky. There is one star, called by its catalogue number HDE 226868, which must have a Partner. This partner star, it seems, has a mass ten or twenty times greater than the sun—yet we can’t see it. Matter from HDE 226868 is being dragged towards this companion star. Could this invisible star, which exerts such a great force, be a black hole Astronomers have evidence of a few other stars too, which might have black holes as companions.
A:the sun is the heaviest star in the universe. B:a star in the sky might have an invisible partner. C:two black holes are dragged towards each other. D:the mass of a star is equal to that of its companion.
{{B}}第三篇{{/B}}
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Black Holes Trigger Stars to
Self-Destruct ? ?Scientists have long understood that super massive black holes weighing millions or billions of suns can tear apart stars that come too close. The black hole’s gravity pulls harder on the nearest part of the star, an imbalance that pulls ’the star apart over a period of minutes or hours, once it gets close enough. ? ?Scientists say this uneven pulling is not the only hazard facing the star. The strain of these unbalanced forces can also trigger a nuclear explosion powerful enough to destroy the star from within. Matthieu Brassart and Jean-Pierre Luminet of the Observatoire de Paris in Meudon, Francel, carried out computer simulations of the final moments of such an unfortunate star’s life, as it veered towards a super massive black hole. ? ?When the star gets close enough, the uneven forces flatten it into a pancake shape. Some previous studies had suggested this flattening would increase the density and temperature inside the star enough to trigger intense nuclear reactions that would tear it apart. But other studies had suggested that the picture would be complicated by shock waves generated during the flattening process and that no nuclear explosion should occur. ? ?The new simulations investigated the effects of shock waves in detail, and found that even when their effects are included, the conditions favor a nuclear explosion. "There will be an explosion of the star—it will be completely destroyed," Brassart says. Although the explosion obliterates the star, it saves some of the star’s matter from being devoured by the black hole. The explosion is powerful enough to hurl much of the star’s matter out of the black hole’s reach, he says. ? ?The devouring of stars by black holes may already have been observed, although at a much later stage. It is thought that several months after the event that rips the star apart, its matter starts swirling into the hole itself. It heats up as it does so, releasing ultraviolet light and X-rays. ? ?If stars disrupted near black holes really do explode, then they could in principle allow these events to be detected at a much earlier stage, says Jules Halpern of Columbia University in New York, US2. "It may make it possible to see the disruption of that star immediately if it gets hot enough," he says. ? ?Brassart agrees. "Perhaps it can be observed in the X-rays and gamma rays, but it’s something that needs to be more studied," he says. Supernova researcher Chris Fryer of the Los Alamos National Laboratory in Los Alamos, New Mexico, US3, says the deaths of these stars are difficult to simulate, and he is not sure whether the researchers have proven their case that they explode in the process. |
A:The black hole could tear apart the star. B:The black bole could trigger a nuclear explosion in the star. C:The black hole could dwindle its size considerably. D:The black hole could devour the star.
{{B}}第三篇{{/B}}
|
Black Holes Trigger Stars to
Self-Destruct ? ?Scientists have long understood that super massive black holes weighing millions or billions of suns can tear apart stars that come too close. The black hole’s gravity pulls harder on the nearest part of the star, an imbalance that pulls ’the star apart over a period of minutes or hours, once it gets close enough. ? ?Scientists say this uneven pulling is not the only hazard facing the star. The strain of these unbalanced forces can also trigger a nuclear explosion powerful enough to destroy the star from within. Matthieu Brassart and Jean-Pierre Luminet of the Observatoire de Paris in Meudon, Francel, carried out computer simulations of the final moments of such an unfortunate star’s life, as it veered towards a super massive black hole. ? ?When the star gets close enough, the uneven forces flatten it into a pancake shape. Some previous studies had suggested this flattening would increase the density and temperature inside the star enough to trigger intense nuclear reactions that would tear it apart. But other studies had suggested that the picture would be complicated by shock waves generated during the flattening process and that no nuclear explosion should occur. ? ?The new simulations investigated the effects of shock waves in detail, and found that even when their effects are included, the conditions favor a nuclear explosion. "There will be an explosion of the star—it will be completely destroyed," Brassart says. Although the explosion obliterates the star, it saves some of the star’s matter from being devoured by the black hole. The explosion is powerful enough to hurl much of the star’s matter out of the black hole’s reach, he says. ? ?The devouring of stars by black holes may already have been observed, although at a much later stage. It is thought that several months after the event that rips the star apart, its matter starts swirling into the hole itself. It heats up as it does so, releasing ultraviolet light and X-rays. ? ?If stars disrupted near black holes really do explode, then they could in principle allow these events to be detected at a much earlier stage, says Jules Halpern of Columbia University in New York, US2. "It may make it possible to see the disruption of that star immediately if it gets hot enough," he says. ? ?Brassart agrees. "Perhaps it can be observed in the X-rays and gamma rays, but it’s something that needs to be more studied," he says. Supernova researcher Chris Fryer of the Los Alamos National Laboratory in Los Alamos, New Mexico, US3, says the deaths of these stars are difficult to simulate, and he is not sure whether the researchers have proven their case that they explode in the process. |
A:No nuclear explosion would be triggered inside the star. B:The star would be destroyed completely. C:Much of the star’s matter thrown by the explosion would be beyond the black hole’s reach. D:The black hole would completely devour the star.
{{B}}第二篇{{/B}}
|
Black Holes Trigger Stars’
Self-destruction ? ?Scientists have long understood that super massive (大块的) black holes weighing. Millions or billions of suns can tear apart stars that come too close. The black hole’s gravity (地心引力) pulls harder on the neatest part of the star, an imbalance that pulls the star apart over a period of minutes or hours, once it gets close enough. ? ?Scientists say this uneven pulling is not the only hazard (冒险) facing the star. The strain of these unbalanced forces can also trigger (触发) a nuclear explosion powerful enough to destroy the star from within. Matthieu Brassart and Jean-Pierre Luminet of the Observatoire of the Paris in Meudon, France, carried out computer simulations of the final moments of such an unfortunate star’s life, as it veered towards a supermassive black hole. ? ?When the star gets Close enough, the uneven forces flatten it into a pancake shape. Some previous studies had suggested this flattening would increase the density and temperature inside the star enough to trigger intense nuclear reactions that would tear it apart (扯开). But other studies had suggested that the picture would he complicated by shock waves generated during the flattening process and that not nuclear explosion should occur. ? ?The new simulations investigated the effects of shock waves in detail, and fund that even when their effects are included; the conditions favor a nuclear explosion. "There will be an explosion of the star. It will be completely destroyed," Brassart says. Although the explosion obliterates the star, it saves some of the start’s matter from being devoured by the black hole. The explosion is powerful enough to hurt much of the star’s matter out of the black hole’s reach, he says. ? ?The devouring of stars by black holes may already have been observed, although at a much later stage. It is thought that several months after the event that rips the star apart, its matter starts swirling into the hole itself. It heats up as it does so, releasing ultraviolet light and X-rays. ? ?If stars disrupted (使分裂) near black holes really do explode, then they could in principle allow these events to be detected at a much earlier stage, says Jules Halpern of Columbia University in New York, US. "It may make it possible to see the disruption of that star immediately if it gets hot enough. " ? ?Brassart aggress. "Perhaps it can be observed in the X-rays and gamma rays, but it’s something that needs to be more studied , "he says. Supernova researcher Chris Fryer of the Los Alamos National Laboratory in Los Almos, New Mexico, US, says the deaths of these stars are difficult to simulate, and he is not sure whether the researchers have proven their case they exploded in the process. |
A:The black hole could tear apart the star. B:The black hole could trigger a nuclear explosion in the star. C:The black hole could dwindle its size considerably. D:The black hole could devour the star.
{{B}}第二篇{{/B}}
|
Black Holes Trigger Stars’
Self-destruction ? ?Scientists have long understood that super massive (大块的) black holes weighing. Millions or billions of suns can tear apart stars that come too close. The black hole’s gravity (地心引力) pulls harder on the neatest part of the star, an imbalance that pulls the star apart over a period of minutes or hours, once it gets close enough. ? ?Scientists say this uneven pulling is not the only hazard (冒险) facing the star. The strain of these unbalanced forces can also trigger (触发) a nuclear explosion powerful enough to destroy the star from within. Matthieu Brassart and Jean-Pierre Luminet of the Observatoire of the Paris in Meudon, France, carried out computer simulations of the final moments of such an unfortunate star’s life, as it veered towards a supermassive black hole. ? ?When the star gets Close enough, the uneven forces flatten it into a pancake shape. Some previous studies had suggested this flattening would increase the density and temperature inside the star enough to trigger intense nuclear reactions that would tear it apart (扯开). But other studies had suggested that the picture would he complicated by shock waves generated during the flattening process and that not nuclear explosion should occur. ? ?The new simulations investigated the effects of shock waves in detail, and fund that even when their effects are included; the conditions favor a nuclear explosion. "There will be an explosion of the star. It will be completely destroyed," Brassart says. Although the explosion obliterates the star, it saves some of the start’s matter from being devoured by the black hole. The explosion is powerful enough to hurt much of the star’s matter out of the black hole’s reach, he says. ? ?The devouring of stars by black holes may already have been observed, although at a much later stage. It is thought that several months after the event that rips the star apart, its matter starts swirling into the hole itself. It heats up as it does so, releasing ultraviolet light and X-rays. ? ?If stars disrupted (使分裂) near black holes really do explode, then they could in principle allow these events to be detected at a much earlier stage, says Jules Halpern of Columbia University in New York, US. "It may make it possible to see the disruption of that star immediately if it gets hot enough. " ? ?Brassart aggress. "Perhaps it can be observed in the X-rays and gamma rays, but it’s something that needs to be more studied , "he says. Supernova researcher Chris Fryer of the Los Alamos National Laboratory in Los Almos, New Mexico, US, says the deaths of these stars are difficult to simulate, and he is not sure whether the researchers have proven their case they exploded in the process. |
A:No nuclear explosion would be triggered inside the star. B:The star would be destroyed completely. C:Much of the star’s matter thrown by the explosion would be beyond the black hole’s reach. D:The black hole would completely devour the star.
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