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 week ago, I had the great pleasure of reading an e-book, When Money Talks, Listen! By Rich Ezzo．It took only about an hour to read.

   When I first received a copy, I thought it was a Get Rich Quick type of publication．Nothing is wrong with Get Rich Quick, but my mind just doesn’t chase after dreams of wealth．I think that if God ever wants me to be rich, he knows where to find my purse.

   When I began reading When Money Talks, Listen!, I was overjoyed to find that Rich Ezzo isn’t money hungry either．He, too, is hungry far more important than money．

Since I love this e-book so much, why wait a week to write the review? Simple．I wanted to see if the effect it had on me was a keeper．After reading the last word of the e-book, I totally agreed with the subtitle which promised to forever change the way we thought about money．I had so many thoughts running around my mind that I had to install(安装) a stoplight to stop some while others made their way into the picture, then I yielded(让路) them as a few ones arrived in town．I had a mental traffic jam, which only goes to show how slow the traffic usually is．

   It has been a week and the effect is the same．I truly do look at money differently and have even done a few things differently this week．This is an e-book you’ll want to read, I promise．I often recommend books to my daughter, and this is one that I didn’t just “suggest”---I left it open at the bottom of the computer and told each one, “Read it, you’ll love it.”

   I would never point someone in a direction I wouldn’t go myself．I urge you to visit the author’s website, Myster Money, and to download the e-book．You won’t regret it.

The author wrote this passage to _________　

       A．strongly recommend an e-book.

　    B．show the author's attitude to money.

　    C．introduce the general idea of an e-book.

　    D．point out Rich Ezzo isn't money hungry.

According to the passage, a Get Rich Quick type of publication ______.

       A．is what the author really cares for

       B．deals with how to make money

       C．is also an e-book written by Rich Ezzo

       D．is more popular than e-books

The author didn't write the review as soon as he finished reading the book because________．

　    A．he was too excited to write anything

　    B．he was not sure whether he did well

　    C．he had to wait for Rich Ezzo's permission

　    D．he wondered if the book would have long influence on him

By saying the underlined sentence in Paragraph 4, the author probably __________.

　    A．shows that the book brought him many new thoughts

　    B．shows how bad the traffic is in town

　    C．describes the difficulty in understanding the book

　    D．explains it's hard to change one's attitude to money

Which of the following is supported by the passage?

      A．The author had known Rich Ezzo before.

　    B．The author hasn't dreamed of getting rich immediately.

　    C．The author always prefers e-books to paper books.

　    D．The author likes Get Rich Quick-type of publications.

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 dam is a man-made structure built across a river. Most dams are built to control a river’s water flow, improve navigation and control flooding. However, some dams are built to produce hydro-electric power.

Hydro-electric power is produced as water passes through a dam, and into a river below. The more water that passes through a dam, the more energy is produced. Once a dam is built, a man-made lake is created behind the dam.

Electricity is produced by a kind of equipment called a turbine(水轮机). Turbines contain metal coils(线圈) surrounded by magnets(磁铁). When the magnets move round rapidly over the metal coils, electricity is produced. Turbines are located inside dams. The falling water makes the magnets go around the coils.

Dams provide clean energy, but they can also harm the environment. Species that use rivers to reproduce are often hurt by dams. In the Northwest of the US, the population of fishes has dropped from 16 million to 2.5 million since hydro-electric plants were built on the Columbia River. Dams all over the world have hurt some species. 

  The highest dam in the Unites States is located near Oroville, California. The Oroville Dam towers 230 meters and is more than a mile wide. This dam was built in 1968, 22 years after the Hoover Dam. The Hoover Dam, on the Nevada-Arizona border controls the Colorado river. It is 221 meters high and has 2.6 million hectare-meters of water.

The highest dam in the world is the Nurek Dam on the Vakhsh River in Tadzikistan, a country in central Asia. This dam is 300 meters tall. 

Which of the following statements is NOT true according to the passage?              

A. Some dams are built for controlling a river’s water flow.

B. Hydro-electric power is usually produced through a dam.

C. Dams can offer energy and they are harmless to the environment.

D. Generally speaking, where there is a dam, there is a man-made lake.

The third paragraph mainly tells us _____.                          

  A. how hydro-electric power is produced

  B. What a turbine is and how it works 

  C. how the magnets and the metal coils work

  D. how the falling water passes through a turbine                     

The dam which controls the Colorado river is ____.                  

A. the Oroville Dam  B. the Hoover Dam  C. the Nurek Dam  D. the Vakhsh Dam