根据以下材料,回答题Black Holes(1) Black holes can be best described as a sort of vacuum, s - 试题答案网问答

第1题

根据下面材料，回答题。 Black HolesMost scientists agree that black holes exist but are nea

根据下面材料，回答题。

Black Holes

Most scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe is not a solid object, like a planet, but it is shaped like a sphere (球体). Astronomers(天文学家) think that at the center of a black hole there is a single point in space with infinite (无限的) density (稠密). This single point is called a singularity (奇点). If the singularity theory is correct, it means that when a massive star collapses, all the material in it disappears into the singularity. The center of a black hole would not really be a hole at all, but an infinitely dense point.

Anything that crosses the black hole is pulled in by its great gravity.

Although black holes do exist, they are difficult to observe. These are the reasons.

？ No light or anything else comes out of black holes. As a result, they are invisible to a telescope.

？ In astronomical terms, black holes are truly. For example, a black hole formed by the collapse of a giant star would have an event horizon (视界) only 18 miles across.

？ The nearest black holes would be dozens of light years away from Earth. One light year is about 6 trillion (万亿) miles. Even the most powerful telescopes could not pick out an object so small at such a great distance.

In 1994 the Hubble Space Telescope provided evidence that black holes exist. There are still answers to be found, however, so black holes remain one of the mysteries of the universe.

Black holes are part of space. 查看材料

A.Right

B.Wrong

C.Not mentioned

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第2题

请根据短文内容，回答题。 Black HolesMost scientists agree that black holes exist but are nea

请根据短文内容，回答题。

Black Holes

Most scientists agree that black holes exist but are nearly impossible to locate. A black hole in the universe is not a solid object, like a planet, but it is shaped like a sphere (球体). Astronomers(天文学家) think that at the center of a black hole there is a single point in space with infinite (无限的 ) density (稠密 ) . This single point is called a singularity (奇点). If the singularity theory is correct, it means that when a massive star collapses, all the material in it disappears into the singularity. The center of a black hole would not really be a hole at all, but an infinitely dense point.＜br＞

Anything that crosses the black hole is pulled in by its great gravity.＜br＞

Although black holes do exist, they are difficult to observe. These are the reasons.＜br＞

No light or anything else comes out of black holes. As a result, they are invisible to a telescope.＜br＞

In astronomical terms, black holes are truly. For example, a black hole formed by the collapse of a giant star would have an event horizon (视界) only 18 miles across.＜br＞

The nearest black holes would be dozens of light years away from Earth. One light year is about 6 trillion (万亿) miles. Even the most powerful telescopes could not pick out an object so small at such a great distance.＜br＞

In 1994 the Hubble Space Telescope provided evidence that black holes exist. There are still answers to be found, however, so black holes remain one of the mysteries of the universe.＜

Black holes are part of space. 查看材料

A.Right

B.Wrong

C.Not mentioned

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第3题

请根据短文内容，回答题。 Black Holes（1) Black holes can be best described as a sort of vacuu

请根据短文内容，回答题。

Black Holes

(1) Black holes can be best described as a sort of vacuum, sucking up everything in space.＜br＞

Scientists have discovered that black holes come from an explosion of huge stars. Stars that are near death can no longer burn due to loss of fuel, and because its temperature can no longer control the gravitational (重力的 ) force, hydrogen ends up putting pressure onto the star&39;s surface until it suddenly explodes then collapses.＜br＞

(2) Black holes come from stars that are made of hydrogen, other gases and a few metals. When these explode it can turn into a stellar-mass (恒星质量) black hole, which can only occur if the star is large enough (should be bigger than the sun) for the explosion to break it into pieces, and the gravity starts to compact every piece into the tiniest particle. Try to see and compare: if a star that&39;s ten times the size of the sun end up being a black hole that&39;s no longer than 70 kilometers, then the Earth would become black hole that&39;s only a fraction of an inch!＜br＞

(3) Objects that get sucked in a black hole will always remain there, never to break free. But remember that black holes can only gobble up (吞噬) objects within a specific distance to it. It&39;s possible for a large star near the sun to become a black hole, but the sun will continue to stay in place. Orbits (轨道) do not change because the newly formed black hole contains exactly the same amount of mass as when it was a star, only this time its mass is totally contracted that it can end up as no bigger than a state.＜br＞

(4)So far, astronomers have figured out that black holes exist because of Albert Einstein&39;s theory of relativity. In the end, through numerous studies, they have discovered that black holes truly exist. Since black holes trap light and do not give off light, it is not possible to detect black holes via a telescope. But astronomers continue to explore galaxies (银河系) , space and the solar system to understand how black holes might evolve. It is possible that black holes can exist for millions of years, and later contribute further process in galaxies, which can eventually lead to creation of new entities. Scientists also credit black holes as helpful in learning how galaxies began to form.

Paragraph 1 __________ 查看材料

A.Is there proof that black holes really exist？

B.What are different types of black holes？

C.How are black holes formed？

D.How were black holes named

E.What happens to the objects around a black hole？

F.What are black holes made of？

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第4题

请根据短文内容，回答题。 Eruptions of Mount Saint HelensOn March 27, the US Government sc

请根据短文内容，回答题。

Eruptions of Mount Saint Helens

On March 27, the US Government scientists made a decision after they predicted the eruption of Mount Saint Helens. They telephoned all state and local officials in the area and told them that a serious eruption was possible at any time. Roads were closed to every one except scientists and forest keepers struggled to keep curious visitors away from the mountain.

Shortly afternoon on March 27, Mount Saint Helens erupted for the first time in 123 years.

People living north of the mountain heard a loud boom that shook their windows, and airline pilots flying near the volcano soon afterwards described a thick black column of ash and steam shooting more than 2,100 meters into the sky.

Later, scientists found that the explosion had made a new crater (大坑) in the top of the mountain, not far from the old crater. The north side of the peak now had a huge bulge (凸出部分)where rock and ice had been pushed out by the eruption.

A second eruption shook the mountain on March 28. It, too, sent up a column of black ash high into the sky. By March 29, scientists flying over the mountain saw that a second crater formed about 9 meters from the first one. Strange blue flames flickered (闪烁) inside the crater and sometimes jumped from one crater to the other.

By April the mountain had erupted several more times and the snow on the north slope of the peak was black with ash. Ash carried by the wind had fallen on towns as far as 240 kilometers away from Mount Saint Helens.

During the first week of April, Mount Saint Helens gave scientists something new to worry about: harmonic tremors (振动) recorded by scientists showed a big eruption would happen. All during April and into May Mount Saint Helens continued to shudder (振动 ) and shoot out ash. By April 8, two craters had merged to from a vast hole nearly a half of a kilometer wide and 250 meters deep.

Scientists&39; main worry during this time was the growing bulge of rock and ice on. the north face of the mountain. By May 7 scientists feared the worst. Their warnings led Washington Governor to set up safety zones around the mountain. The inner "red" zone was open to scientists only. The outer "blue" zone was open only to people who got special permits. But in spite of these warnings, some people got past the road barriers and risked their lives trying to get close to the volcano.

American scientists predicted that Mount Saint Helens was to erupt soon. 查看材料

A.Right

B.Wrong

C.Not mentioned

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第5题

根据以下材料，回答题Native American PotteryThere are several American Indian groups in the

根据以下材料，回答题

Native American Pottery

There are several American Indian groups in the Southwest that still make beautiful pottery.

Some of this pottery may be sold at fairly high prices. But the makers consider their work as more than a commercial enterprise. By using methods handed downfor generations， the potters express their pride in their cultural inheritance （遗产） .

Some of the most interesting pottery is made by the Pueblo Indians. There are 21 individual pueblos in Arizona and New Mexico. Several are famous for their craftsmanship.To make a pot，these potters use a clay base and add long thin coils of clay toit in a spiral pattern. When they have reached the size they want， they use an implement such as a rock or shell to smooth the surfaces of the pot.

How a pot is decorated and fired depends on the traditions of the group making it. Traditional pottery produced by the Acoma， who have lived for centuries on a high mesa in NewMexico， is first painted with a clay slip. The resulting pots: which are prizedfor their delicacy and strength，may be left white. They may also be painted with black and white patterns or with a combination of black， orange， and brown.

Very distinctive （忒别的，有特色的） black pottery comes from the Sail Ildefonso and Santa Clara pueblos. The black color is the result of carbon being released from the animal manure （粪肥） in which the pot is fired. Some artisans hand -rub this ware to a shiny gloss. Others cut patterns into it: resulting in a part shiny: part fiat surface. Potters at Sail lldefonso make many types of wares. Potters at Santa Clara are especially known for wedding jars-jars with two necks connected by a handle.

Other groups such as the Hopi and the Cochiti also make pottery. Each group uses distinctive methods and produces distinctive .forms and designs.

In the first paragraph the word "commercial" means 查看材料

A.advertising products on TV

B.selling and business

C.large-scale

D.artistic

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第6题

根据以下材料，回答题Tales of the Terrible PastIt is not the job of fiction writers to analy

根据以下材料，回答题

Tales of the Terrible Past

It is not the job of fiction writers to analyze and interpret history. Yet by writing about the past in a vivid and compelling manner， storytellers can bring earlier eras to life and force readers to consider them seriously. Among those taking on the task of recounting history are some black writers who attempt to examine slavery from different points of view.

Nobel Prize-winning author Toni Morrison deals specifically with the legacy of slavery in her book Beloved. The main character in this novel， a former slave called Sethe， lives in Ohio in the years following the Civil War， but she cannot free herself from her horrific memories. Through a series of flashbacks and bitter reminiscences， the reader learns how and why Sethe escaped from the plantation she had lived on; the fate of her husband， who also tried to escape; and finally， what happened to the child called Beloved. Morrison"s scenes of torture and murder are vivid and strongly convey the desperation of the slaves and the cruelty of their owners.

Charles Johnson"s Middle Passage approaches slavery from a different， yet no less violent，vantage point. His main character， Rutherfprd Calhoun， is a ne"er-do-well free black American who stows away on a slave ship bound for Africa to collect its "cargo". Put to work after he is discovered，Calhoun witnesses firsthand the appalling conditions in which the captured Africans are transported.

When they finally rebel and take over the ship， he finds himself in the middle—— and is forced to come to terms with who he is and what his values are.

Neither Beloved nor Middle Passage is an easy read， but both exemplify African American writers" attempts to bring significant historical situations alive for a modem audience.

This passage is mostly about 查看材料

A.the causes of slavery in America

B.black writers in the late 20th century

C.why Morrison and Johnson wrote the books they did

D.two novels that deal with slavery

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第7题

回答题。 Eruptions of Mount Saint HelensOn March 27, the U.S. Government scientists made

回答题。

Eruptions of Mount Saint Helens

On March 27, the U.S. Government scientists made a decision after they predicted the eruption of Mount Saint Helens. They telephoned all state and local officials in the area and told them that a serious eruption was possible at any time, Roads were closed to every one except scientists and forest keepers struggled to keep curious visitors away from the mountain.

Shortly after noon on March 27, Mount Saint Helens erupted for the first time in 123 years. People living north of the mountain heard a loud boom that shook their windows, and airline pilots flying near the volcano soon afterwards described a thick black column of ash and steam shooting more than 2100 meters into the sky.

Later, scientists found that the explosion had made a new crater (大坑 ) in the top of the mountain, not far from the old crater. The north side of the peak now had a huge bulge (凸出部分 ) where rock and ice had been pushed out by the eruption.

A second eruption shook the mountain on March 28. It, too, sent up a column of black ash high into the sky. By March 29, scientists flying over the mountain saw that a second crater formed about 9 meters from the first one. Strange blue flames flickered (闪烁 ) inside the crater and sometimes jumped from one crater to the other.

By April the mountain had erupted several more times and the snow on the north slope of the peak was black with ash. Ash carried by the wind had fallen on towns as far as 240 kilometers away from Mount Saint Helens.

During the first week of April, Mount Saint Helens gave scientists something new to worry about : harmonic tremors (震动 ) recorded by scientists showed a big eruption would happen. All during April and into May Mount Saint Helens continued to shudder (震动 ) and shoot out ash. By April 8, two craters had merged to from a vast hole nearly a half of a kilometer wide and 250 meters deep.

Scientists&39; main worry during this time was the growing bulge of rock and ice on the north face of the mountain. By May 7 scientists feared the worst. Their warnings led Washington Governor to set up safety zones around the mounmin. The inner "red" zone was open to scientists only. The outer "blue" zone was open only to people who got special permits. But in spite of these warnings, some people got past the road barriers and risked their lives trying to get close to the volcano.

＞

American scientists predicted that Mount Saint Helens was to erupt soon. 查看材料

A.Right

B.Wrong

C.Not mentioned

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第8题

根据以下材料，回答题Racial PrejudiceIn some countries where racial prejudice is acute， viol

根据以下材料，回答题

Racial Prejudice

In some countries where racial prejudice is acute， violence has been taken for granted as a means of solving differences， and this is not even questioned. There are countries 51_________ the white man imposes his rule by brute （粗暴的） force， there are countries where the black man protests by 52_________ fire to cities and by looting and pillaging （抢劫）. Important people on both sides， who would appear to be reasonable men， get up and calmly argue in 53_________ of violence as if it were a legitimate （合法的） solution，54_________ any other. What is really frightening， what really 55_________ you with despair， is the realization that when it comes to the crunch（关键时刻）， we have made no actual 56_________ at all. We may wear collars and ties instead of war-paint， but our instincts remain basically unchanged. The whole of the recorded 57_________ of the human race， that tedious documentation of violence， has taught us absolutely nothing. We have still not learnt that 58_________ never solves a problem but makes it more acute. The sheer horror， the blood and the suffering. 59_________ nothing.

No solution ever comes to 60_________ the morning after when we dismally （阴郁地） contemplate the smoking ruins and wonder what hit us.

The truly reasonable men who 61_________ where the solutions lie are finding it harder and harder to get a hearing. They are despised， mistrusted and even persecuted 62_________ their own kind because they advocate such apparently outrageous things as law enforcement. If half the energy that goes into 63_________ acts were put to good use， if our efforts were directed at 64_________ up the slums and ghettos （贫民窟）， improving living-standards and providing education and employment for all，we would not have gone a long way to 65_________ at a solution.

回答（51）题查看材料

A.when

B.why

C.where

D.what

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第9题

The center of a black hole is empty. 查看材料A.RightB.W

The center of a black hole is empty. 查看材料

A.Right

B.Wrong

C.Not mentioned

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第10题

根据以下材料，回答题Electric BackpackBackpacks are convenient. They can hold your books， yo

根据以下材料，回答题

Electric Backpack

Backpacks are convenient. They can hold your books， your lunch， and a change of clothes leaving your hands free to do other things. Someday， if you don"t mind carrying a heavy load， your backpacks might also power your MP3 player， keep your cell phone running， and maybe even light your way home.

Lawrence C. Rome and his colleagues from the University of Pennsylvania in Philadelphia and the Marine Biological Laboratory in Woods Hole， Mass. have invented a backpack thatmakes electricity from energy produced while its wearer walks. In military actions search-and-rescue operations and scientific field studies， people rely increasingly on cellphones global positioning system （GPS） receivers，night-vision goggles， and other battery powered devices to get around and do their work. The backpack"s electricity-generating feature could dramatically reduce the amount of a wearer"s load now devoted to spare batteries， report Rome and his colleagues in the Sept.9 science.

The backpack"s electricity-creating powers depend on springs used to hang a cloth pack from its metal frame. The frame. sits against the wearer"s back， and the whole pack moves up and down as the person walks. A gear mechanism converts vertical movements of the pack to rotary motions of an electrical generator， producing up to 7.4 watts.

Unexpectedly， tests showed that wearers of the new backpack alter their gaits in response to the pack"s oscillations， so that they carry loads more comfortably and with less effort than they do ordinary backpacks. Because of that surprising advantage， Rome plans to commercialize both electric and non-electric versions of the backpack.

The backpack could be especially useful for soldiers， scientists， mountaineers， and emergency workers who typically carry heavy backpacks. For the rest of us， power-generating backpacks could make it possible to walk， play video games， watch TV， and listen to music， all at the same time. Electricity-generating packs aren"t on the market yet， but if you do get one eventually just make sure to look both ways before crossing the street!

Backpacks are convenient because __________. 查看材料

A.they can be verylarge

B.they can hold as many things as you want to carry

C.your handsare freed to do other things

D.you do not have to carry things withyou

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根据以下材料，回答题Black Holes（1） Black holes can be best described as a sort of vacuum， s