A camera, a glove, a hand tool, even a toothbrush… they are all up there, above the clouds, going around and around the Earth. There are also thousands of pieces of metal and plastic. Some of them are only about the size of a fingernail. Many are much larger. Scientists consider all these objects to be space junk, and they are a problem.

　　　 Since people first launched rockets into space in the 1950s, we have been leaving behind all sorts of things. Much of the space junk is made up of little pieces of things that were once bigger objects, until they struck each other and broke apart. Sometimes larger pieces survive the extreme heat through the atmosphere and hit the ground or the ocean at great speeds.

　　　 But space junk falling on housetops is not the biggest worry. Scientists are concerned about the Kessler syndrome. It is named after the American scientist who first thought of the idea in 1978. Imagine what happens when an empty rocket strikes another while orbiting the Earth. Two big things become many smaller things. They then hit other things. The pieces get smaller and smaller until they form a cloud of junk that blocks the path of future space vehicles.

　　　 Marco Castronuovo, an Italian Space Agency researcher, suggested launching a satellite into space that would get very close to some of the larger pieces of space junk. The satellite would connect a small rocket to the useless object. When the rocket explodes, it pushes the junk into a lower and slower orbit, nearer the Earth. After a time, the junk burns up in the atmosphere.

　　　 Scientists have been concerned about space junk for many years. Right now, the costs of the clean- up have been too great. Mr. Castronuovo says his system could be put in place for a much more reasonable amount of money.

67.　 What does the underlined part “space junk” in Paragraph 1 refer to?

A.It refers to small pieces of things that were once bigger objects.

B.It refers to objects that survived the extreme heat through the atmosphere.

C.It refers to clouds that are made up of small objects in space.

D.It refers to all kinds of objects that have been left behind in space.

68.Why do scientists consider the Kessler syndrome a big problem?

A.Space junk clouds are likely to block the path of spacecraft.

B.An empty rocket might strike a spacecraft orbiting the Earth.

C.Space junk might fall onto the Earth, causing damage.

D.Space junk becomes bigger and bigger until hard to get rid of.

69.What is mainly talked about in the passage?

A.Smaller objects come together to form clouds of space junk.

B.Human beings are responsible for space junk.

C.Space junk is a big problem human beings have to find ways to solve.

D.An Italian researcher has found a good way to remove space junk.

70.What is the author’s attitude towards Marco Castronuovo’s method of cleaning up space junk?

A.　 Doubtful. 　　　　　　 B.　 Objective.　　　　　　 C.　 Favorable.　　 D.　 Disapproving.

What makes a person a scientist? Does he have ways or tools of learning that are different from those of others? The answer is “no”. It is not the tools a scientist uses but how he uses these tools that makes him a scientist. You will probably agree that knowing how to use a power is important to a carpenter. You will probably agree, too, that knowing how to investigate(调查),how to discover information, is important to everyone. The scientist, however, goes one step further, he must be sure that he has a reasonable answer to his questions and that his answer can be confirmed by other persons. He also works to fit the answers he gets to many questions into a large set of ideas about how the world works.

The scientist’s knowledge must be exact. There is no room for half right or right just half the time. He must be as nearly right as the conditions permit. What works under one set of conditions at one time must work under the same conditions at other times. If the conditions are different, any changes the scientist observes in a demonstration must be explained by the changes in the conditions. This is one reason that investigations are important in science. Albert Einstein, who developed the theory of relativity, arrived at this theory through mathematics. The accuracy of his mathematics was later tested through investigations. Einstein’s ideas were shown to be correct. A scientist uses many tools for measurements. Then the measurements are used to make mathematical calculations that may test his investigations.

What makes a scientist according to the passage?

A.  The tools he uses.              B.  His ways of learning.

C.   The way he uses his tools.     D.  The various tools he use

“The scientist, however, goes one step further,” the author says this to show       。

the importance of information    

B. the importance of thinking

C. the difference between scientists and ordinary people

D. the difference between carpenters and people with other jobs.

A sound scientific theory should be one that       .

A. does not only work under one set of conditions at one time, but also works under the same conditions at other times

B. leaves no room for improvement

C. does not allow any change even under different conditions

D. can be used for many purposes

What is the main idea of the passage?

A. Scientists are different from ordinary people.

B. The theory of relativity.

C. Exactness is the core（核心）of science.

D. Exactness and way of using tools are the keys to the making of a scientist.

What makes a person a scientist? Does he have ways or tools of learning that are different from those of others? The answer is “no”. It is not the tools a scientist uses but how he uses these tools that makes him a scientist. You will probably agree that knowing how to use a power is important to a carpenter. You will probably agree, too, that knowing how to investigate(调查),how to discover information, is important to everyone. The scientist, however, goes one step further, he must be sure that he has a reasonable answer to his questions and that his answer can be confirmed by other persons. He also works to fit the answers he gets to many questions into a large set of ideas about how the world works

The scientist’s knowledge must be exact. There is no room for half right or right just half the time. He must be as nearly right as the conditions permit. What works under one set of conditions at one time must work under the same conditions at other times. If the conditions are different, any changes the scientist observes in a demonstration must be explained by the changes in the conditions. This is one reason that investigations are important in science. Albert Einstein, who developed the theory of relativity, arrived at this theory through mathematics. The accuracy of his mathematics was later tested through investigations. Einstein’s ideas were shown to be correct. A scientist uses many tools for measurements. Then the measurements are used to make mathematical calculations that may test his investigations.

51.What makes a scientist according to the passage?

A.  The tools he uses.            B.  His ways of learning.

C.   The way he uses his tools.     D.  The various tools he use

52.“The scientist, however, goes one step further,” the author says this to show       。

the importance of information    

B. the importance of thinking

C. the difference between scientists and ordinary people

D. the difference between carpenters and people with other jobs.

53. A sound scientific theory should be one that       .

A. does not only work under one set of conditions at one time, but also works under the same conditions at other times

B. leaves no room for improvement

C. does not allow any change even under different conditions

D. can be used for many purposes

54. What is the main idea of the passage?

Scientists are different from ordinary people.

The theory of relativity.

Exactness is the core（核心）of science.

Exactness and way of using tools are the keys to the making of a scientist.

Reading is a task that we all do either for enjoyment or education, but sometimes the book we have to read may lack the attraction. Here are some tips on avoiding getting bored while reading.
Try to step into the world of literature(文学) you are reading. __56___ If the wind is blowing, imagine how the leaves move with each movement of air.
Make your reading area unlike your sleeping area. If you sleep with the radio on, then shut it off. __57__ Make the area you read in an area that feels almost uncomfortable to sleep in. This will keep you from becoming sleepy.
__58__ If you are reading for a book report , then take breaks from time to time to put what you are reading into some kind of context（语境） that you can put into the report.
Take a break once in a while. __59___ You’d better offer yourself short breaks while reading in case you are too tired, which may make you give up.
Find a friend. ___60__ Try to read the same book. Even if you read different books, you can tell him or her how good the book is. Also, a friend can encourage you to read.

Reading is a task that we all do either for enjoyment or education, but sometimes the book we have to read may lack the attraction. Here are some tips on avoiding getting bored while reading.

Try to step into the world of literature(文学) you are reading. __56___ If the wind is blowing, imagine how the leaves move with each movement of air.

Make your reading area unlike your sleeping area. If you sleep with the radio on, then shut it off. __57__ Make the area you read in an area that feels almost uncomfortable to sleep in. This will keep you from becoming sleepy.

__58__ If you are reading for a book report , then take breaks from time to time to put what you are reading into some kind of context（语境） that you can put into the report.

Take a break once in a while. __59___ You’d better offer yourself short breaks while reading in case you are too tired, which may make you give up.

Find a friend. ___60__ Try to read the same book. Even if you read different books, you can tell him or her how good the book is. Also, a friend can encourage you to read.

E. Don’t just read the words on the page; picture them in your mind.

F. Determine what you are supposed to get from the reading material.

G. If you don’t like lights on when you are asleep, then turn on the lights.