题目内容
（请给出正确答案）
A．who did
B．has done
C．and doing
D．to do
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更多“Tennis star Chris Evert, who r…”相关的问题
A．who did
B．has done
C．and doing
D．to do
Tennis champion Chris Evert visualized her opponent's style. for imitation.
A．Y
B．N
C．NG
A．relieve
B．exceed
C．conflict
D．prevent
The Christmas Tree
In pre-Christian Europe, people believed that trees (fruit trees and evergreens in particular) were embodiment of powerful beings. In the fourteenth and fifteenth centuries, the designated miracle play for December 25 was the story of Adam and Eve and in this play the chief prop was an apple-hung evergreen called the paradise tree. In the sixteenth century, German families began bringing evergreens into their homes during the Christmas season. By the seventeenth century, they were known as Christbaiime (Christ trees) and were being decorated with fruits, candies, cookies, candles and wafers resembling the eucharistic host.
The first Christmas trees in America were set up by German immigrants in the 1820s and the almost universal adoption of the custom dates from the 1910s. Now at Christmas time decorated trees stand in about two-thirds of American homes. The modem American tree is usually covered with colored balls and strings of colored lights. The star on top represents the Star in the East which guided the three Wise Men to Bethlehem.
Christmas is traditionally celebrated on______.
A．December 24
B．December 25
C．December 30
D．December 31
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.
Something destructive could happen to a star that gets too close to a black hole. Which of the following destructive statements is NOT mentioned in the passage？
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.
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.
Something destructive could happen to a star that gets too close to a black hole. Which of the following statements is NOT mentioned in the passage？
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.
【C1】
A．to
B．in
C．at
D．for
What does Chris order？
A．fish
B．steak
C．chicken
A．She has more self-confidence than Chris.
B．She works with Chris in the same division.
C．She has more management experience than Chris.
D．She is competing with Chris for the new job. Passage Three
