题目列表(包括答案和解析)
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
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
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
A latest national survey has found that over half of China's netizens (网民) are suffering from various mental problems although some 62 percent of them claim at the same time that they are happy on the whole anyway.
This is the result of China's first White Paper on Netizens’ Health Conditions issued on Wednesday by 39.net, China's largest authoritative website on health sciences. It is the first most comprehensive health survey on netizens’ health situation ever conducted in China in ten years’ time. The white paper came out after two months of online and offline research that involved over 150 thousand netizens, covering topics and questions on health knowledge, mental situation, sense of health, and living habits.
According to the white paper, more than 70 percent of China's netizens say they are suffering from mental problems such as bad memory, anxiety, depression, and a lack of confidence. And a similar 72 percent of them also say they are often suffering from diseases like insomnia, dizziness, joint degeneration and achings. Meanwhile, another 53 percent of netizens believe that white collar employees who have bigger work pressures are more likely to catch mental problems.
The white paper adds, doing almost no sports and spending long time surfing online lead to the above mentioned health problems among netizens. Only 9 percent of netizens take up sports on weekends while over 40 percent stay home, surfing. And only 16 percent netizens can assure more than eight hours’ sleeping daily.
At present, China has a netizen population of 162 million, with a monthly consumption of 186 yuan, or about 25 dollars, on Internet surfing.
The national survey on netizens’ health situation ________.
A. was conducted on Wednesday B. was carried out online and offline
C. is conducted every year D. covered about half a million netizens
Which of the following has the closest meaning to the underlined part “white collar”?
A. White clothes. B. Office workers.
C. White offices. D. White people.
All the following factors have been mentioned to cause the health problems among netizens EXCEPT ________.
A. shopping online B. spending long time online
C. heavy work pressures D. doing no sports
What’s the main idea of the passage?
A. China has a large netizen population.
B. The Internet has a negative influence on people.
C. Many netizens in China have mental problems.
D. How to surf the Internet safely and healthily.
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
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