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A black hole is created when a large star burns out. Like our sun, stars are unbelievably hot furnaces (熔炉) that burn their own matter as fuel. When most of the fuel is used up, the star begins to die.
The death of a star is not a quiet event. First there is a huge explosion. As its outer layer is blasted off into space, the dying star shines as brightly as a billion suns.
After the explosion gravity pulls in what’s left of the star. As the outside of the star sinks toward the center, the star gets smaller and smaller. The material the star is made of becomes tightly packed together. A star is so dense that a teaspoon of matter from it weighs billion of pounds.
The more the star shrinks, the stronger the gravity inside it becomes. Soon the star is very tiny, and the gravity pulling it in is unbelievably strong. In fact, the gravity is so strong that it even pulls light into the star! Since all the light is pulled in, none can go out. The star becomes black when there is no light. Then a black hole is born!
That’s what we know about black holes. What we don’t know is this: What happens inside a black hole after the star has been squeezed into a tiny ball? Does it keep getting smaller and smaller forever? Such a possibility is hard to imagine.
But if the black hole doesn’t keep shrinking, what happens to it? Some scientists think black holes are like doorways to another world. They say that as the star disappears from our universe, it goes into another universe. In other words a black hole in our universe could turn into a “white hole” in a different universe. As the black hole swallows light, the white hole shines brightly—somewhere else. But where? A different place, perhaps, or a different time — many years in the past or future.
Could you travel through a black hole? Right now, no. Nothing we know of could go into a black hole without being crushed. So far the time being, black hole must remain a mystery.
Black holes are a mystery—but that hasn’t stopped scientists from dreaming about them. One scientist suggested that in the future we might make use of the power of black holes. They would supply all of Earth’s energy needs, with plenty to spare. Another scientist wondered if a black hole could some day be used to swallow earthly waste—a sort of huge waste disposal(处理) in the sky!
When the star begins to die ______.
A. there is no fuel left in it B. its outer layer goes into space first
C. a huge explosion will happen D. it doesn’t give off light any longer
Which of the following doesn’t help produce a black hole?
A. The gravity inside the star is very strong. B. The light can’t go out of the star.
C. The star becomes smaller and smaller D. The dying star shines very brightly.
The black hole ______.
A. continues becoming smaller and smaller all the time
B. goes into another universe and becomes a white hole
C. can pull in everything we know of in the world
D. will appear at another place at a different time
What’s the best title for this passage?
A. A New Scientific Discovery: Black Holes
B. How Do Black Holes Come Into Being?
C. What Are Black Holes?
D. Travel Through A Black Hole
查看习题详情和答案>>A black hole is created when a large star burns out. Like our sun, stars are unbelievably hot furnaces(熔炉) that burn their own matter as fuel. When most of the fuel is used up, the star begins to die.
The death of a star is not a quiet event. First there is a huge explosion. As its outer layer is blasted off into space, the dying star shines as brightly as a billion suns.
After the explosion gravity pulls in what’s left of the star. As the outside of the star sinks toward the center, the star gets smaller and smaller. The material the star is made of becomes tightly packed together. A star is so dense that a teaspoon of matter from it weighs billion of pounds.
The more the star shrinks, the stronger the gravity inside it becomes. Soon the star is very tiny, and the gravity pulling it in is unbelievably strong. In fact, the gravity is so strong that it even pulls light into the star! Since all the light is pulled in, none can go out. The star becomes black when there is no light. Then a black hole is born!
That’s what we know about black holes. What we don’t know is this: What happens inside a black hole after the star has been squeezed into a tiny ball? Does it keep getting smaller and smaller forever? Such a possibility is hard to imagine.
But if the black hole doesn’t keep shrinking, what happens to it? Some scientists think black holes are like doorways to another world．They say that as the star disappears from our universe, it goes into another universe. In other words a black hole in our universe could turn into a “white hole” in a different universe. As the black hole swallows light, the white hole shines brightly — somewhere else. But where? A different place, perhaps, or a different time — many years in the past or future.
Could you travel through a black hole? Right now, no. Nothing we know of could go into a black hole without being crushed．So far the time being, black hole must remain a mystery.
Black holes are a mystery—but that hasn’t stopped scientists from dreaming about them. One scientist suggested that in the future we might make use of the power of black holes. They would supply all of Earth’s energy needs, with plenty to spare. Another scientist wondered if a black hole could some day be used to swallow earthly waste—a sort of huge waste disposal (处理) in the sky!
When the star begins to die ______.
A．there is no fuel left in it B．its outer layer goes into space first
C．a huge explosion will happen D．it doesn’t give off light any longer
Which of the following doesn’t help produce a black hole?
A．The gravity inside the star is very strong.
B．The light can’t go out of the star.
C．The star becomes smaller and smaller
D．The dying star shines very brightly.
The black hole ______.
A．continues becoming smaller and smaller all the time
B．goes into another universe and becomes a white hole
C．can pull in everything we know of in the world
D．will appear at another place at a different time
What’s the best title for this passage?
A．A New Scientific Discovery: Black Holes
B．How Do Black Holes Come Into Being?
C．What Are Black Holes?
D．Travel Through A Black Hole
查看习题详情和答案>>A senior United Nations Children’s Fund(UNICEF) official on May 29 praised China for its remarkable achievements in children’s welfare.
A. H. M. Farook, UNICEF’s operations area officer for China and Mongolia said that China “can be very satisfied to tell the whole world what can be done with limited resources to help its children to grow healthily and happily.”
China’s child population makes up one-fifth of the world’s total. “The reason behind the tremendous(巨大的) achievement is China’s long tradition of caring for children both at home and in society,” he said.
“What’s more is that Chinese people have always given special attention to children who are in special need.” The UN official made the remarks when addressing a group of 50 children and staff from the Beijing Children’s Welfare Home at the Shangri-la Hotel, Beijing.
The hotel invited the orphans to share snacks, sing, dance and play games at a park inside the hotel for a “Share the Sunshine” party, as a prelude(前奏) to celebrations to mark the Children’s Day.
The Beijing children’s Welfare Home, set up soon after New China was founded in 1949, has at present more than 400 children.
A leading official of the welfare institution said that the children live a happy life and that the agency spends 400—500 yuan a month for an average orphan. An average Chinese workers earned 440 yuan a month during the first quarter this year.
Gu Xiaojin, deputy secretary-general of the China Youth Development Foundation(CYDF), said people from all walks of life have contributed to the welfare of the Chinese children.
She said that CYDF set up the Project Hope in 1989, which calls on people across the country to donate money to help poor children to continue their schooling.
By the end of last year, she said, CYDF had collected nearly 700 million yuan in donations, which has helped the establishment of 2, 074 Hope primary schools and enabled more than 1. 25 million dropouts to return to school classrooms.
Three “Hope Stars” also attended the party. They were model teenagers chosen among students who are economically supported by the Project Hope to further their nine-year compulsory studies in the poverty-stricken regions. They will be torchbearers for the Chinese Team for the up coming Atlanta Olympic Games this year.
Children can grow healthily and happily as long as _______.
A. parents take good care of them both at home and in society
B. the whole society care for children as well as their parents
C. Schools and teachers pay much attention to the growth of children
D. Chinese people always give special attention to children who are in special need
Every year the Beijing Children’s Welfare Home spends _______ on the orphans
A. 1, 920, 000 yuan B. 2, 160, 000 yuan
C. Over 2, 400, 000 yuan D. 2, 200, 000 yuan or so
CYDF collected 700 million yuan with the purpose of _______.
A. reducing dropouts
B. helping homeless orphans
C. supporting the Chinese Team for the coming Atlanta Olympic Games
D. establishing 2, 074 Hope primary schools all over the country
We can infer from the text that _______.
A. Every Chinese child has its own special need, so we should pay special attention to each.
B. All the children in the poverty-stricken regions of China are too poor to go to school.
C. Ever since liberation. the Chinese Communist Party has been concerned about the growth of the younger generation.
D. With the help of UNICEF officials, there are no more dropouts in China.
It is possible that this passage was written in _______.
A. 1992 B. 1996 C. 1998 D. 2000
查看习题详情和答案>>A black hole is created when a large star burns out. Like our sun, stars are unbelievably hot furnaces (熔炉) that burn their own matter as fuel. When most of the fuel is used up, the star begins to die.
The death of a star is not a quiet event. First there is a huge explosion. As its outer layer is blasted off into space, the dying star shines as brightly as a billion suns.
After the explosion gravity pulls in what’s left of the star. As the outside of the star sinks toward the center, the star gets smaller and smaller. The material the star is made of becomes tightly packed together. A star is so dense that a teaspoon of matter from it weighs billion of pounds.
The more the star shrinks, the stronger the gravity inside it becomes. Soon the star is very tiny, and the gravity pulling it in is unbelievably strong. In fact, the gravity is so strong that it even pulls light into the star! Since all the light is pulled in, none can go out. The star becomes black when there is no light. Then a black hole is born!
That’s what we know about black holes. What we don’t know is this: What happens inside a black hole after the star has been squeezed into a tiny ball? Does it keep getting smaller and smaller forever? Such a possibility is hard to imagine.
But if the black hole doesn’t keep shrinking, what happens to it? Some scientists think black holes are like doorways to another world. They say that as the star disappears from our universe, it goes into another universe. In other words a black hole in our universe could turn into a “white hole” in a different universe. As the black hole swallows light, the white hole shines brightly—somewhere else. But where? A different place, perhaps, or a different time — many years in the past or future.
Could you travel through a black hole? Right now, no. Nothing we know of could go into a black hole without being crushed. So far the time being, black hole must remain a mystery.
Black holes are a mystery—but that hasn’t stopped scientists from dreaming about them. One scientist suggested that in the future we might make use of the power of black holes. They would supply all of Earth’s energy needs, with plenty to spare. Another scientist wondered if a black hole could some day be used to swallow earthly waste—a sort of huge waste disposal(处理) in the sky!
When the star begins to die ______.
A. there is no fuel left in it B. its outer layer goes into space first
C. a huge explosion will happen D. it doesn’t give off light any longer
Which of the following doesn’t help produce a black hole?
A. The gravity inside the star is very strong. B. The light can’t go out of the star.
C. The star becomes smaller and smaller D. The dying star shines very brightly.
The black hole ______.
A. continues becoming smaller and smaller all the time
B. goes into another universe and becomes a white hole
C. can pull in everything we know of in the world
D. will appear at another place at a different time
What’s the best title for this passage?
A. A New Scientific Discovery: Black Holes
B. How Do Black Holes Come Into Being?
C. What Are Black Holes?
D. Travel Through A Black Hole
查看习题详情和答案>>A teddy bear from Cumbria is launching into space to raise cash for charity(慈善).
Terence, an experienced traveller who has been to Iraq, will be the guest of honour on aviation(航行) legend Burt Rutan’s Spaceship One when it flies above Earth. The mission takes off from California on September 29, and on his return the cuddly toy will be auctioned off(拍卖) in aid of the North Air Ambulance Appeal(北部空中救护服务中心).
Spaceship One is the world’s first private spacecraft, and is competing for a prestigious space travel prize. Chief executive of the Great North Air Ambulance Service (GNAAS), Graham Pickering, said “flying officer” Terence had been handed over to the RAF six months ago and staff had been receiving postcards from him ever since.
He said, “Terence was a fundraising idea that really took off. We have received pictures of him in a U2 craft, trying parachuting and even looking drunk and disorderly. When the RAF finally discharge him he will be a very rare bear indeed—we just hope he does not burn up on re-entry to Earth.”
GNAAS, which needs charitable donations of more than ￡2m a year, has three air ambulances(空中救护机).
Peter Bond, spokesman for the Royal Astronomical Society, said Terence’s safety was not guaranteed. He said, “This is a new and experimental craft and this will only be the second time it has flown. During its first voyage it developed technical problems but hopefully they have now been resolved.”
Since May, Terence has spent time with members of 100 Squadron(空军中队) based at RAF Leeming in Basra, Iraq, and at air shows with performing fighter planes.
Spaceship One will fly 100km (62 miles) above the Earth’s surface, just breaking through the planet’s atmosphere.
If it repeats the feat(技艺) inside two weeks, it will claim the $10m Ansari X-Prize set up to encourage the private space flight business.
Terence is ________.
A. a real bear living in England B. an experienced astronaut
C. an air force officer D. a toy bear
We can infer that________.
A. after this space flight, Spaceship One will get the $10m Ansari X-Prize
B. it is dangerous for a spaceship to re-enter the earth atmosphere
C. Terence will be very safe on the flight
D. Spaceship One is just an ordinary plane
Which of the following is true of Spaceship One?
A. Spaceship One is the world’s first spacecraft.
B. The purpose of its flight is to collect money for the charity.
C. The purpose of its flight is to compete for a prestigious space travel prize.
D. Spaceship One has never flown.
Which of the following is the best title?
A. Teddy bear astronaut to lift off B. Spaceship One to lift off
C. Space flight D. The toy bear will be auctioned off
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