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 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 study published in September suggests there is a surprising way to get people to avoid unhealthy foods: change their memories. Scientist Elizabeth Loftus of the University of California at Irvine asked volunteers to answer some questions on their personalities (个性) and food experiences. “One week later,” Loftus says, “we told those people we'd fed their answers into our smart computer and it came up with an account of their early childhood experiences.” Some accounts included one key additional detail (细节): “You got sick after eating strawberry ice-cream.” The researchers then changed this detail into a manufactured (人为促生的) memory through leading questions—Who were you with? How did you feel? By the end of the study, up to 41% of those given a false memory believed strawberry ice-cream once made them sick, and many said they'd avoid eating it.
When Loftus published her findings, she started getting calls from people begging her to make them remember hating chocolate or French fries. Unfortunately, it's not that easy. False memories appear to work only for foods you don't eat on a regular basis. But most important, it is likely that false memories can be implanted (灌输) only in people who are unaware of the mental control. And lying to a patient is immoral, even if a doctor believes it's for the patient's benefit.
Loftus says there's nothing to stop parents from trying it with their overweight children. “I say, wake up—parents have been lying about Father Christmas for years, and nobody seems to mind. If they can prevent diseases caused by fatness and all the other problems that come with that, you might think that's a more moral lie. Decide that for yourself.”
72. Why did Loftus ask the volunteers to answer some questions?
A. To improve her computer program. B. To find out their attitudes towards food.
C. To find out details she can make use of D. To predict what food they'll like in the future.
73. What did Loftus find out from her research?
A. People believe what the computer tells them.
B. People can be led to believe in something false.
C. People tend to forget their childhood experiences.
D. People are not always aware of their personalities.
74. According to the study, people may stop having a certain food if they ________.
A. learn it is harmful for health
B. lie to themselves that they don't want it
C. are willing to let doctors control their minds
D. think they once had a bad experience of eating it
75. What is the biggest concern with the method?
A. Whether it is moral. B. Who it is best for.
C. When it is effective. D. How it should be used.
We once had a poster competition in our fifth grade art class.
“You could win prizes，’’our teacher told US as she wrote the poster information on the blackboard. She passed out sheets of construction paper while continuing，“The first prize is ten dollars. You just have to make sure that the words on the blackboard appear somewhere on your poster. ”
We studied the board critically. Some of US looked with one eye and held up certain colors against the blackboard，rocking the sheets to the fight or left while we conjured up our designs. Others twisted their hair around their fingers or chewed their erasers while deep in thought. We had plans for that ten—dollar grand prize，each and every one of US. I'm going to spend mine on candies，one hopeful would announce，while another practiced looking serious，wise and rich.
Everyone in the class made a poster. Some of us used parts of those fancy paper napkins， while others used nothing but colored construction paper. Some of US used big designs，and some of us preferred to gather our art tidily down in one comer of our poster and let the space draw the viewer's attention to it. Some of US would wander past the good students’ desks and then return to our own projects with a growing sense of hopelessness. It was yet another grown-up trick of the soil they seemed especially fond of。making all of US believe we had a fair chance，and then always—always—rewarding the same old winners.
I believe I drew a sailboat，but I can’t say that with any certainty. I made it. I admired it. I determined it to be the very best of all of the posters I had seen，and then I turned it in.
Minutes passed.
No one came along to give me the grand prize，and then someone distracted me，and I probably never would have thought about that poster again.
I was still sitting at my desk，thinking，What poster? When the teacher gave me an envelope with a ten-dollar bill in it and everyone in the class applauded for me.
46. What was the teacher's requirement for the poster?
A. It must appear in time.
B. It must be done in class.
C. It must be done on a construction sheet.
D. It must include the words on the blackboard.
47. The underlined phrase in paragraph 3 most probably means _____________.
A. formed an idea for
B. made an outline for
C. made some space for
D. chose some colors for
48. After the teacher’s words，all the students in the class _________.
A. 1ooked very serious
B. thought they would be rich
C. began to think about their designs
D. began to play games
49. After seeing the good students’ designs，some students _________.
A. 1oved their own designs more
B. thought they had a fair chance
C. put their own designs in a comer
D. thought they would not win the prize
50. We can infer from the passage that the author ______________.
A. enjoyed grown-up tricks very much
B. 1oved poster competitions very much
C. felt surprised to win the competition
D. became wise and rich after the competition
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