Alzheimer’s disease is a major national health problem. Nearly 2 million Americans over the age of 65 have Alzheimer’s disease. It is a leading cause of death among the elderly. But Alzheimer’s disease is not confined （限于） to the aged. There may be a million or more people under the age of 65 suffering from the disease.
　　At one time, people suffering from the disease were said to be “getting old”. The disease was thought to be a natural part of growing old, but it is now known that Alzheimer’s disease strikes young and old alike. It is an organic （器官的） disease that destroys brain cells.
　　Alzheimer’s disease affects the patient’s memory, speech, and movement. In the beginning stages of the disease, the patient may seem slightly confused. He may have trouble speaking, then the patient’s memory begins to fail. He may forget dates, numbers, names and plans.
As the disease progresses, the patient may not recognize family and friends. These symptoms（症状） often cause terrible anxiety in the patient. He may feel lost and frightened. Sometimes the patient reacts with wild and bad behavior.
　　In the last stages of the disease, the patient may not be able to take care of himself. He may have lost the ability to speak and walk.
　　Scientists don’t know exactly what causes Alzheimer’s disease. It may be caused by a virus （病毒）.It may be caused by a poisonous substance（物质） in the environment. At present, there is no cure for the disease. But there are ways to slow its progress. Exercise and physical treatment can help the patients of this disease.
【小题1】The main idea of the passage is that Alzheimer’s disease ________.

Did you ever look up at the moon and think you saw a man’s face there? When the moon is round and full, the shadows(影子) of the moon mountains and the lines of the moon valleys sometimes seem to show a giant nose and mouth and eyes. At least, some people think so.
　　If there were a man on the moon—instead of mountains and valleys that just look like the face of a man—what would he be like?
　　He would not be like anyone you know. He would not be like anyone anybody knows.
　　If the man on the moon were bothered by too much heat or cold the way Earth people are, he could not stay on the moon.
　　The moon becomes very, very hot. It becomes as hot as boiling water. And the moon becomes very, very cold. It becomes colder than ice.
　　Whatever part of the moon the sun shines on is hot and bright. The rest of the moon is cold and dark.
　　If the man on the moon had to breathe to stay alive, he couldn’t live on the moon because there’s no air there. He’d have to carry an oxygen tank, as astronauts do. There’s no food on the moon, either. Nothing grows—not even weeds（grass）.
　　If the man on the moon liked to climb mountains, he would be very happy. There are many high places there, such as the raised land around the holes, or craters(火山口), of the moon. Some of these rims are as tall as Earth’s highest mountains.
　　But if the man on the moon liked to swim, he would be unhappy. There is no water on the moon—just dust and rock.
　　When you think of what it’s like on the moon, you may wonder why it interests our scientists. One reason is that the moon is Earth’s nearest neighbor—it is the easiest place in space to get to.
　　Going back and forth between the moon and Earth, astronauts will get a lot of practice in space travel. Things learned on moon trips will be of great help to astronauts who later take long, long trips to some of the planets.
　　Scientists are also interested in the moon because it has no air. The air that surrounds Earth cuts down the view of the scientists who look at the stars through telescopes. A telescope on the moon would give them a clearer, closer view of the stars.（words: 411）
【小题1】What is the reason why our scientists are interested in the moon.?

Did you ever look up at the moon and think you saw a man’s face there? When the moon is round and full, the shadows(影子) of the moon mountains and the lines of the moon valleys sometimes seem to show a giant nose and mouth and eyes. At least, some people think so.

　　If there were a man on the moon—instead of mountains and valleys that just look like the face of a man—what would he be like?

　　He would not be like anyone you know. He would not be like anyone anybody knows.

　　If the man on the moon were bothered by too much heat or cold the way Earth people are, he could not stay on the moon.

　　The moon becomes very, very hot. It becomes as hot as boiling water. And the moon becomes very, very cold. It becomes colder than ice.

　　Whatever part of the moon the sun shines on is hot and bright. The rest of the moon is cold and dark.

　　If the man on the moon had to breathe to stay alive, he couldn’t live on the moon because there’s no air there. He’d have to carry an oxygen tank, as astronauts do. There’s no food on the moon, either. Nothing grows—not even weeds（grass）.

　　If the man on the moon liked to climb mountains, he would be very happy. There are many high places there, such as the raised land around the holes, or craters(火山口), of the moon. Some of these rims are as tall as Earth’s highest mountains.

　　But if the man on the moon liked to swim, he would be unhappy. There is no water on the moon—just dust and rock.

　　When you think of what it’s like on the moon, you may wonder why it interests our scientists. One reason is that the moon is Earth’s nearest neighbor—it is the easiest place in space to get to.

　　Going back and forth between the moon and Earth, astronauts will get a lot of practice in space travel. Things learned on moon trips will be of great help to astronauts who later take long, long trips to some of the planets.

　　Scientists are also interested in the moon because it has no air. The air that surrounds Earth cuts down the view of the scientists who look at the stars through telescopes. A telescope on the moon would give them a clearer, closer view of the stars.（words: 411）

1.What is the reason why our scientists are interested in the moon.?

A．The moon is beautiful.

B．The moon is different from the earth.

C．The moon is Earth’s nearest neighbor—it is the easiest place in space to get to.

D．The moon is the easiest place in space to get to and it has no air, unlike Earth.

2.The underlined word “rim” in the Paragraph 8 means _________ .

A．ball              B．hill               C．round edge        D．height

3.What is the main thought of the passage?

A．We can learn much from research on the Moon.

B．There may be human beings on the moon.

C．If there were a man on the Moon, there would be many similarities between the man on the Moon and on the Earth.

D．A telescope on the Moon would help scientists have a clearer, closer sight of the stars.

B
It is natural that children are curious about the world around them. For example, they want to know how their hearts beat. They want to know why the ocean water tastes salty.
　　As children grow up, they become curious about different kinds of things. When they are babies, they are interested in the parts of their bodies and in the smiles of their mothers. They become interested in the physical world around them: the plants, the animals, the sky. Later, they become interested in the things that people have made: wheels, bicycles, cars. And when they are adults, their curiosity continues. Sometimes this curiosity leads to a career (生涯、职业) in science.
　　Scientists spend their lives trying to find out about the world．Those who work with the earth sciences study the earth, the oceans, and the skies. Other scientists who study living things work with the biological sciences. A third group of scientists study the physical sciences, e. g. physics, chemistry .
　　These scientists have already discovered a lot about our world．For example, they tell us why your heart beats fast when you run. They say that when you are quiet, your heart normally beats sixty-five or seventy-five times a minute. Your heart is a pump (泵) that pumps blood to all parts of the body. The blood carries oxygen and nutrition. When you run, your muscles work very hard and use the nutrition that the blood carries to them. The muscles need oxygen, too . So your brain sends a signal to the heart. The signal means that the muscles need more nutrition and oxygen. Then the heart beats fast and sends blood quickly to the muscles. It may beat 90 to 140 times a minute.
　　Of course, scientists cannot answer all of our questions. If we ask, “Why does the ocean water taste salty” scientists will say that the salt comes from rocks. When a rock gets very hot or very cold, it cracks. Rain falls into cracks. The rain then carries the salt into the earth and into the rivers. The rivers carry the salt into the ocean. But then we ask , “What happens to the salt in the ocean? The ocean does not get saltier every year.” Scientists are not sure about the answer to this question.
　　We know a lot about our world, but there are still many answers that we do not have, and we are curious.
45．According to the passage, which of the following statements is true?
　  A．People are curious in the same way.
　  B．People in different countries are interested in different things.
　  C．Men and women are curious about different things.
　  D．People of different ages are interested in different things
46．Scientists who work with the biological sciences study____.
A．the earth , the oceans and the sky          B．man-made things
C．plants and animals                               D．ocean water
47．When you run, your muscles need ____.
A．more nutrition and oxygen    B．more signals    C．more salt   D．water
48．A rock cracks _____.
A．in wet regions                                     B．in dry regions
C．at very high or very low temperatures               D．when salty water falls in