There is no creature that does not need sleep or complete rest every day.
If you want to know why,just try going without sleep for a long period of time.You will discover that your mind and body would become too tired to work properly.You would become irritable and find it hard to think clearly or concentrate on your work.So sleep is quite simply the time when the cells of your body recover from the work of the day and build up supplies of energy for the next period of activity.
One of the things we all know about sleep is that we are unconscious in sleep.We do not know what is going on around us.But that doesn’t mean the body stops all activity.The important organs continue to work during sleep,but most of the body functions are slowed down.
For example,our breathing becomes slower and deeper.The heart beats more slowly,and the blood pressure is lower.Our arms and legs become limp(柔软的)and muscles are at rest.It would be impossible for our body to relax to such an extent if we were awake.So sleep does for us what the most quiet rest can not do.
Your body temperature becomes lower when you are asleep,which is the reason people go to sleep under some kind of covers.And even though you are unconscious,many of your reflexes(反射动作)still work.For instance,if someone tickles(使觉得痒)your foot,you will put it away in your sleep,or even brush a fly from your forehead.You do these things without knowing it.
40.If you don’t have as much sleep as your body needs,you will.
C.keep your attention on your work
D.easily get angry
41.The cells of your body develop supplies of energy.
A.when you are asleep
B.when you recover from your work of the day
C.in the next period of activity
D.when you are quiet
42.In the clause“…that we are unconscious in sleep”(Para.3),the word“unconscious”means.
D.not knowing what is happening around
D词语理解题。本句出现于文章的第三段第一句，接下来的一句是对unconscious一词的进一步解释，即do not know what is going on around us。
43.When you are sleeping,.
A.all of you reflexes stop working
B.most of your reflexes stop working
C.many of your reflexes still work
D.all of your reflexes still work
C推理判断题。文章第三段最后一句的意思是，睡眠中，身体的重要器官继续工作，但是身体大部分的功能放慢了,且从最后一段“…many of your reflexes still work”一句我们得出，答案为C。
Space is a dangerous place，not only because of meteors but also because of rays from the sun and other stars.The atmosphere again acts as our protective blanket on earth.Light gets through，and this is essential for plants to make the food which we eat.Heat，too，makes our environment endurable.Various kinds of rays come through the air from outer space，but enormous quantities of radiation from the sun are screened off.As soon as men leave the atmosphere they are exposed to this radiation.But their spacesuits or the walls of their spacecraft，if they are inside,do prevent a lot of radiation damage.
Radiation is the greatest known danger to explorers in space.The unit of radiation is called“rem”.Scientists have reason to think that a man can put up with far more radiation than 0.1 rem without being damaged;the figure of 60 rems has been agreed on.The trouble is that it is extremely difficult to be sure about radiation damage—a person may feel perfectly well，but the cells of his or her sex organs may be damaged，and this will not be discovered until the birth of deformed(畸形的)children or even grandchildren.Missions of the Apollo flights have had to cross belts of high radiation and，during the outward and return journeys，the Apollo crew accumulated a large amount of rems.So far，no dangerous amounts of radiation have been reported，but the Apollo missions have been quite short.We simply do not know yet how men are going to get on when they spend weeks and months outside the protection of the atmosphere，working in a space laboratory.Drugs might help to decrease the damage done by radiation，but no really effective ones have been found so far.
44.According to the first paragraph，the atmosphere is essential to man in that.
A.it protects him against the harmful rays from space
B.it provides sufficient light for plant growth
C.it supplies the heat necessary for human survival
D.it screens off the falling meteors
45.We know from the passage that.
A.exposure to even tiny amounts of radiation is fatal
B.the effect of exposure to radiation is slow in coming
C.radiation is avoidable in space exploration
D.astronauts in spacesuits needn’t worry about radiation damage
46.It can be inferred from the passage that.
A.the Apollo mission was very successful
B.protection from space radiation is no easy job
C.astronauts will have deformed children or grandchildren
D.radiation is not a threat to well-protected space explorers
B推理判断题。由最后一句“Drugs might…but no really effective ones have been found so far.”可知，目前人类还没有找到有效的方法去避免辐射的危害，所以免受辐射危害并非易事，故选B。
47.The best title for this passage would be.
A.The Atmosphere and Our Environment
B.Research on Radiation
C.Effects of Space Radiation
D.Importance of Protection Against Radiation
How men first learned to invent words is unknown;in other words,the origin of language is a mystery.All we really know is that men,unlike animals,somehow invented certain sounds to express thoughts and feelings,actions and things,so that they could communicate with each other;and that later they agreed upon certain signs,called letters,which could be combined to represent those sounds and which could be written down.Those sounds,whether spoken,or written in letters,we call words.
The power of words,then,lies in their associations—the things they bring up before our minds.Words become filled with meaning for us by experience;and the longer we live,the more certain words recall to us the glad and sad events of our past;and the more we read and learn,the more the number of words that mean something to us increases.
Great writers are those who not only have great thoughts but also express these thoughts in words which appeal powerfully to our minds and emotions.This charming and telling use of words is what we call literary(文字的)style.Above all,the real poet is a master of words.He can convey his meaning in words which sing like music,and which by their position and association can move men to tears.We should therefore learn to choose our words carefully and use them accurately,or they will make our speech silly and rude.
48.The origin of language.
A.is a legend handed down from the past
B.is reflected in sounds and letters
C.dates back to the prehistoric period
D.is a problem not yet solved
D事实细节题。文章第一段第一句指出,我们还不知道人们第一次是怎样创造单词的，换句话说，语言的来源仍是个谜(the origin of language is a mystery),还没有得到解决。故选D。
49.One of the reasons why men invented certain sounds to express thoughts and actions is that.
A.they could agree upon certain signs
B.they could write them down
C.they could communicate with each other
D.they could combine them
50.What is true about words?
A.They are used to express feelings only.
B.They can not be written down.
C.They are represented either by sounds or letters.
D.They are visual letters.
51.The real power of words exists in their.
D推理判断题。由文章第二段第一句“The power of words,then,lies in their associations—the things they bring up before our minds.”可知,words的魅力在于它的代表性功能(representative function)。
It seems so natural to put up an umbrella to keep the water off when it rains.But actually the umbrella was not invented as protection against rain.Its first use was as a shade against the sun!
Nobody knows who first invented it,but the umbrella was used in very ancient times.Probably the first to use it were the Chinese,as early as the eleventh century B.C.
We know that the umbrella was used in ancient Egypt and Babylon as a sunshade.And there was a strange thing connected with its use:it became a symbol of honour and authority.In the Far East in ancient times the
umbrella was allowed to be used only by royalty or by those in high office.
In Europe,the Greeks were the first to use the umbrella as a sunshade.And the umbrella was in common use in ancient Greece.But it is believed that the first persons in Europe to use the umbrella as protection against the rain were the ancient Romans.
During the Middle Ages,the use of the umbrella practically disappeared.Then it appeared again in Italy in the late sixteenth century.And again it was considered a symbol of power and authority.By 1680,the umbrella appeared in France,and later on in England.
By the eighteenth century,the umbrella was used against rain throughout most of Europe.Umbrellas have not changed much in style during all this time,though they have become much lighter in weight.It wasn’t until the twentieth century that women’s umbrellas began to be made,in a whole variety of colours.
52.Which of the following statements is NOT true about the umbrella?
A.No one exactly knows who was the inventor of the umbrella.
B.The umbrella was first invented to be used as protection against the sun.
C.The umbrella changed much in style in the eighteenth century.
D.In Europe the Greeks were the first to use the umbrella as a sunshade.
53.A strange feature of the umbrella’s use is that it was used as.
A.protection against rain
B.a shade against the sun
C.a symbol of honour and power
D.a way of women’s decoration
54.In Europe,the umbrella was first used against the rain.
B.in ancient Egypt
55.This passage talks mainly about.
A.how the umbrella was invented
B.why the umbrella was so popular in Europe
C.the development of the umbrella
D.who needed umbrella first