A Brown University sleep researcher has some advice for people who run high schools: Don’t start classes so early in the morning. It may not be that the students who nod off at their desks are lazy. And it may not be that their parents have failed to enforce (确保) bedtime. Instead, it may be that biologically these sleepyhead students aren’t used to the early hour.

“Maybe these kids me being asked to rise at the wrong time for their bodies,” says Mary Carskadon, a professor looking at problem of adolescent  (青春期的) sleep at Brown’s School of Medicine.

Carskadon is trying to understand more about the effects of early school time in adolescents. And, at a more basic level. she and her team are trying to learn more about how the biological changes of adolescence affect sleep needs and patterns.

Carskadon says her work suggests that adolescents may need more sleep than they did at childhood, no less, as commonly thought.

Sleep patters change during adolescence, as any parent of an adolescent can prove. Most adolescents prefer to stay up later at nigh and sleep later in the morning. But it’s not just a matter of choice their bodies are going through a change of sleep patters.

All of this makes the transfer from middle school to high school―which may start one hour earlier in the morning  ---- all the more difficult , Carskadon says. With their increased need for sleep and their biological clocks set on the “sleep late, rise late” pattern, adolescent are up against difficulties when it conics to trying to be up by 5 or 6 a.m. for a 7:30 a.m. first hell. A short sleep on a desktop may be their body’s way of saying. “I need a timeout.”

48. Carskadon suggests that high schools should not start classes so early in the morning because ________.

A. it is really tough for parents to enforce bedtime

B. it is biologically difficult for students to rise early

C. students work so late at night that they can’t get up early

D. students are so lazy that they don’t like to go to school early

49. The underlined phrase “nod off” most probably means “ _______”.

A. turn around    B. agree with others  C. full asleep

D. refuse to work

50. What might be a reason for the hard transfer middle school to high school?

A. Adolescents depend more on their parents.

B. Adolescents have to choose their sleep patterns.

C. Adolescents sleep better than they did at childhood.

D. Adolescents need more sleep than they used to.

51. What is the test mainly about?

A. Adolescent heath care.      B. Problems in adolescent learning.

C. Adolescent sleep difficulties.   D. Changes in adolescent sleep needs and patterns.

A woman was in a hurry to go to the airport. She told the cab driver to drive quickly. She was so absorbed in her own thoughts that she was not aware they were going by a different route.
Suddenly, a man got inside the cab. He took her handbag where she had placed her visa, passport, and all her money for the trip.
The driver, who was in cahoots with the robber, left her in the middle of that dark street. She cursed the world for being so mean to her, and thought how unlucky she was in that situation.
That very same night, she heard some shocking news．Tears flowed down her face．Flight 230,which was the plane that she was supposed to have boarded, had crashed．If she had not lost her precious belongings, she could have lost something far more important—her life．
Sometimes bad things really happen．We lose money, fail our exams, or are rejected by others．There are times when nothing seems to go our way．
So what should we do about it? Should we be disappointed? The answer is a resounding “No!" We must get rid of all these frustrations and start all over again in the consistent faith that we will get what we deserve．
Don't waste your time and energy on things that can't be changed．Continuous worrying will only affect your health and you'll be doing much more damage than what was previously done．
What if it was the other way round? What if we never ran out of good luck?
There was a man who won the lottery．He thought he was the luckiest person in the world．He became greedy and wasted all his money on everything he could get his hands on．
One day, he made it to the front page of the newspaper again．But this time, it was a different story．He had been killed because of his riches．
If you attain good luck, you can never be too secure about it．Hope for protection and guidance．Life is so unpredictable．You never know what will happen next．
Live one day at a time．we sometimes subject ourselves to unnecessary emotional trouble．We ask ourselves: "What if I don't get this done in time?" or "What if my family leaves me and I've got no one else to turn to?"
Live for the moment．Do what must be done for the present and the future will turn out just fine． Believe me．And believe in yourself．As Captain Planet always says: "The power is yours!"
【小题1】The underlined phrase "in cahoots with" in Paragraph 3 probably means "____"．

A new study gives us the warning that about thirty percent of the world's people may not have enough water by the year 2025.
A private American organization called Population Action International did the new study. It says more than three-hundred-thirty-five-million people lack enough water now. The people live in twenty-eight countries. Most of the countries are in Africa or the Middle East.
P-A-I researcher Robert Engelman says by the year 2025, about three-thousand-million people may lack water. At least 18 more countries are expected to have severe water problems. The demand for water keeps increasing. Yet the amount of water on Earth stays the same.
Mr. Engelman says the population in countries that lack water is growing faster than in other parts of the world. He says population growth in these countries will continue to increase.
The report says lack of water in the future may result in several problems. It may increase health problems. Lack of water often means drinking waters not safe. Mr. Engelman says there are problems all over the world because of diseases, such as cholera, which are carried in water. Lack of water may also result in more international conflict. Countries may have to compete for water in the future. Some countries now get sixty percent of their fresh water from other countries. This is true of Egypt, the Netherlands, Cambodia, Syria, Sudan, and Iraq. And the report says lack of water would affect the ability of developing to improve their economies. This is because new industries often need a large amount of water when they are beginning.
The Population Action International study gives several solutions to the water problem. One way, it says, is to find ways to use water for more than one purpose. Another way is to teach people to be careful not to waste water. A third way is to use less water of agriculture.
The report also says long-term solutions to the water problem must include controls on population growth. It says countries cannot provide clean water unless they slow population growth by limiting the number of children people have.
【小题1】__________ are expected to have severe water problems by the year 2025

A black hole is a place in space where gravity pulls so much that even light cannot get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.

Because no light can get out, people can’t see black holes. Space telescopes with special tools can help find black holes. The special tools can see how stars that are very close to black holes act differently from other ones.

Black holes can be big or small. Scientists think the smallest black holes are as small as just one atom. These black holes are very tiny but have the mass of a large mountain. Mass is the amount of matter, or “staff”, in an object.

Another kind of black hole is called “stellar”(星球黑洞). Its mass can be up to 20 times more than the mass of the sun. There may be many stellar mass black holes in Earth’s galaxy. Earth’s galaxy is called the Milky Way.

The largest black holes are called “supermassive”(超大质量黑洞). These black holes have masses that are more than one million suns together. Scientists have found proof that every large galaxy contains a supermassive black hole at its center. The supermassive black hole at the center of the Milky Way galaxy has a mass equal to about four million suns and would fit inside a very large ball that could hold a few million Earths.

Scientists think the smallest black holes formed when the universe began. Stellar black holes are made when the center of a very big star falls in upon itself, or falls apart. When this happens, it exploded part of the star into space. Scientists think supermassive black holes were made at the same time as the galaxy they are in.

A black hole can not be seen because strong gravity pulls all of the light into the middle of the black hole. But scientists can see how the strong gravity affects the stars and gas around the black hole. Scientists can study stars to find out if they are flying around, or orbiting a black hole.

When a black hole and a star are close together, high-energy light is made. This kind of light cannot be seen with human eyes. Scientists use satellites and telescopes in space to see the high-energy light.

1.The gravity of a black hole may become so strong that light cannot get out when ____________.

A. the star is going to die          

B. special tools are used on it

C. other stars come close to it      

D. it is seen from the space telescopes

2.According to the passage, which of the following is NOT true?

A. A black hole can be very tiny but extremely heavy.

B. The gravity of a black hole holds all light in its center.

C. Scientists observe high-energy light through their own eyes.

D. Some small black holes came into being as early as the universe.

3.The underlined word “galaxy” in Paragraph 5 means __________.

A. a black hole                       B. the Milky Way

C. a series of stars                    D. a planet near the earth

4.What does the last sentence in Paragraph 5 suggest?

A. Neither the sun nor the earth is as heavy as a black hole.

B. There is a supermassive black hole at the center of the Milky Way.

C. The supermassive black hole had existed before the Milky Way was formed.

D. There is a reason why the large black holes are called “supermassive”.

5.The last two paragraph mainly focus on the question of _________.

A. what a black hole is        

B. how black holes form

C. how big black holes are    

D. how scientists know about black holes

A new study gives us the warning that about thirty percent of the world's people may not have enough water by the year 2025.

A private American organization called Population Action International did the new study. It says more than three-hundred-thirty-five-million people lack enough water now. The people live in twenty-eight countries. Most of the countries are in Africa or the Middle East.

P-A-I researcher Robert Engelman says by the year 2025, about three-thousand-million people may lack water. At least 18 more countries are expected to have severe water problems. The demand for water keeps increasing. Yet the amount of water on Earth stays the same.

Mr. Engelman says the population in countries that lack water is growing faster than in other parts of the world. He says population growth in these countries will continue to increase.

The report says lack of water in the future may result in several problems. It may increase health problems. Lack of water often means drinking waters not safe. Mr. Engelman says there are problems all over the world because of diseases, such as cholera, which are carried in water. Lack of water may also result in more international conflict. Countries may have to compete for water in the future. Some countries now get sixty percent of their fresh water from other countries. This is true of Egypt, the Netherlands, Cambodia, Syria, Sudan, and Iraq. And the report says lack of water would affect the ability of developing to improve their economies. This is because new industries often need a large amount of water when they are beginning.

The Population Action International study gives several solutions to the water problem. One way, it says, is to find ways to use water for more than one purpose. Another way is to teach people to be careful not to waste water. A third way is to use less water of agriculture.

The report also says long-term solutions to the water problem must include controls on population growth. It says countries cannot provide clean water unless they slow population growth by limiting the number of children people have.

1.__________ are expected to have severe water problems by the year 2025

A．No countries       B．18 countries       C．46 countries       D．28 countries

2.All the following are true except____________.

A．Lack of water may cause conflict between countries

B．Egypt now has enough fresh water

C．There are solutions to the water problem

D．New industries need a lot of water

3.It can be inferred that _____________.

A．There is connection between providing clean water and slowing population growth

B．Lack of water may also result from international conflict

C．The ability of developing has nothing to do with lack of water.

D．It is not known whether diseases have something to do with lack of water

4.What is the solution to the water problem for a long time?

A．Not to waste water.                      B．Less developing industries.

C．Less international conflict.                 D．Control the population

5.The best title of the passage would be __________.

A．World Conflict                          B．Diseases and Water

C．World Water Shortage                   D．Population and Water