Vitamin D helps bones and muscles grow strong and healthy. Low levels of vitamin D can lead to diseases such as rickets (佝偻病), mainly found in children. The thinning of bone is a common problem as people, especially women, get older.
But more and more research is suggesting that vitamin D might also help prevent many diseases. The easiest way to get vitamin D is from sunlight. The sun’s ultraviolet (紫外线的) rays react with skin cells to produce vitamin D. But many people worry about getting skin cancer and skin damage from the sun. As a result they stay out of the sun. Also, darker-skinned people produce less vitamin D than lighter-skinned people. The amount also decreases in older people and those living in northern areas that get less sunlight.
Not many foods naturally contain vitamin D. Foods high in this vitamin include oily fish and fish liveroils (鱼肝油). Farmed fish have only about one-fourth as much vitamin D as wild fish. Small amounts of vitamin D are found in beef liver, cheese and egg yolks. But most of the vitamin D in the American diet comes from foods such as milk.
Research in the last several years has shown that low levels of vitamin D may increase the risk of heart attacks in men and deaths from some cancers. More doctors are now having their patients tested for their vitamin D levels. But as research continues, some experts worry that if people take too much vitamin D, it might act as a poison. Also, skin doctors warn people to be careful with sun exposure because of the risk of skin cancer.
【小题1】The first paragraph is mainly about 　　　　.

第三部分 阅读理解（共20小题。 每小题2分，满分40分）

　　阅读下列短文，从每题所给的四个选项（A、B、C和D）中，选出最佳选项，并在答题卡上将该项涂黑。

Drying food is a simple, low-cost way to keep food safe for eating. Drying removes water that small organisms use to break down food into other substances. Some of these substances may be poisonous to humans.

A device that uses the sun is a good way to dry food. There are several kinds of solar dryers. The easiest to build is called the direct dryer. The sun shines directly on the food being dried. The direct dryer is a box with holes in it so that air can enter and leave the box. It has a cover made of clear glass or plastic. When the sun shines into the box, heat is produced. The heat is trapped inside the box and cannot escape back through the cover. The heat dries the food.

The solar dryer works better if the sides of the box are black. This is because dark colors hold heat while light colors reflect it. One way to make the sides black is to use wood that has been blackened by fire.

If you use black paint instead, be sure the paint contains no lead. Lead is poisonous to people, especially children.

The box can be made of almost any material such as wood, concrete or sheet metal. The dryer should be two meters long, one meter wide and twenty-three to thirty centimeters deep. The sides and bottom should have additional material, called insulation, to keep the heat from escaping.

The surface on which the food is placed should permit air to enter from below and pass through to the food. A surface made of wires with small square openings works very well. You should use wire with the largest openings or squares that do not allow the food to fall through. Air that comes in from below the wire surface will also carry away water evaporated from the food as it dries.

A direct dryer will dry most vegetables in two-and-one-half to four hours at temperatures from forty-three to sixty-three degrees Celsius. Fruits take longer, from four to six hours at the same temperatures.

51.Solar food drying is fast, safe and low-cost. It is also healthy because nutrients such as vitamin C are kept in the food. Solar dried food also tastes and looks good.

51.In which way will the food be fried quickly?

A.Let the sun shine directly on the food.

B.Make the sides of the box black.

C.Make wood be the sides of the box.

D.The box must be made of blackened wood.

52.What does the underlined word “evaporate” in the 6th paragraph mean?

A. sink into   B. change into gas or steam    C. flow away    D. flow into

53.According to the text., which of the following statements is true?

A.Water in the food may cause poisonous substances.

B.The sun shines into the box and be trapped.

C.Dark colours hold heat better than light colours.

D.It takes longer for vegetable to be fried.

54.What’s the text mainly about?

A.the way to dry food.

B.Solar Food Dryers

C.The device that uses the sun

D.The way to keep food safe.

　　When did you last see a polar bear? On a trip to a zoo, perhaps? If you had attended a winter activity in New York a few years ago, you would have seen a whole polar bear club. These "Polar Bears" are people who meet frequently in the winter to swim in freezing cold water. That day, the air temperature was 3℃, and the water temperature was a bit higher. The members of the Polar Bear Club at Coney Island, New York are usually about the age of 60. Members must satisfy two requirements. First, they must get along well with everyone else in the group, this is very important because there are so many different kinds of people in the club. Polar Bears must also agree to swim outdoors at least twice a month from November through February.
　　Doctors do not agree about the medical effects of cold-water swimming. Some are worried about the dangers of a condition in which the body's temperature drops so low that finally the heart stops. Other doctors, however, point out that there is more danger of a heart attack during summer swimming because the difference between the air temperature and water temperature is much greater in summer than in winter.
The Polar Bears themselves are satisfied with the benefits (or advantages) of cold-water swimming. They say that their favorite form of exercise is very good for the circulatory system(循环系统) because it forces the blood to move fast to keep the body warm. Cold-water swimmers usually turn bright red after a few minutes in the water. A person who turns blue probably has a very poor circulatory system and should not try cold-water swimming.
　　The main benefits(or advantages) of cold-water swimming are probably mental. The Polar Bears love to swim year-round; they find it fun and relaxing. As one 70-year-old woman says. "When I go into the water, I pour my troubles into the ocean and let them float away."
51. The members of the Polar Bear Club must meet the following requirements except that_____ .
　A. they should be easy to make friends with
　B. they must swim outdoors at least 8 times in the four cold months
　C. they must agree to swim outdoors from November through February
　D. they must reach the age of 60
52. Doctors _____ .
　A. encourage people to take part in cold-water swimming actively
　B. point out the possible danger of blood illness during cold-water swimming
　C. believe swimming is helpful both in winter and in summer
　D. have different ideas about the medical effects of cold-water swimming
53. According to the passage, some doctors believe it is true that _____ .
　A. you are healthy if cold-water swimming turns your skin color blue
　B. cold-water swimming causes more heart attacks in summer than in winter
　C. cold-water swimming can make the body temperature dangerously high
　D. Polar Bears are bears swimming in freezing water
54. The Polar Bears like to swim all the year round, for _____ .
　A. they can remain young   B. it is an easy way to keep the body warm in winter
　C. they find it enjoyable and interesting D. they might meet fewer troubles in life
55. The passage is mainly about _____ .
a group of cold-water swimming lovers                  B. the polar bears' life  
　C. doctors' ideas about cold-water swimming            D. the requirements of the Polar Bear Club

Is there anything more important than health? I don’t think so. “Health is the greatest wealth(财富),” wise people say. You can’t be good at your studies or work well when you are ill.　　     
Speaking about health, I can’t help telling you a funny story.　　
An old gentleman came to see the doctor. The man was very ill. He told the doctor about his weakness, memory loss and serious problems with his heart and lungs. The doctor examined him and said there was no medicine for his disease.　   
He told his patient to go to a quiet place for a month and have a good rest. He also advised him to eat a lot of meat, drink two glasses of red wine every day and take long walks. In other words, the doctor advised him to follow the rule: “Eat at pleasure, drink with measure and enjoy life as it is.” The doctor also said that if the man wanted to be well again, he shouldn’t smoke more than one cigarette a day.　　
A month later the gentleman came into the doctor’s office. He looked cheerful and happy. He thanked the doctor and said that he had never felt a healthier man.　　
“But you know, doctor,” he said, “it’s not easy to begin smoking at my age.”
【小题1】The writer thinks that 　　　　.

It was Monday. Mrs. Smith's dog was hungry, but there was not any meat in the house.

　　Considering that there was no better way. Mrs. Smith took a piece of paper, and wrote the following words on it：“Give my dog half a pound of meat.” Then she gave the paper to her dog and said gently：“Take this to the butcher（* person whose job is selling meat）and he's going to give you your lunch today.”

　　Holding the piece of paper in its mouth, the dog ran to the butcher's. It gave the paper to the butcher. The butcher read it carefully, recognized that it was really the lady's handwriting and soon did it as he was asked to. The dog was very happy, and ate the meat up at once.

　　At noon, the dog came to the shop again. It gave the butcher a piece of paper again. After reading it, he gave it half a pound of meat once more.

　　The next day, the dog came again exactly at noon. And as usual, it brought a piece of paper in the mouth. This time, the butcher did not take a look at paper, and gave the dog its meat, for he had regarded the dog as one of his customers（*people who buy sth. from a shop）.

　　But, the dog came again at four o'clock. And the same thing happened once again. To the butcher's more surprise, it came for the third time at six o'clock, and brought with it a third piece of paper. The butcher felt a bit puzzled. He  said to himself, “This is a small dog. Why does Mrs. Smith give it so much meat to eat today?”

Looking at the piece of paper, he found that there were not any words on it！

1.Mrs. Smith treated her little dog quite 　　　.

2.It seemed that the dog knew well that the paper Mrs. Smith gave it ______ .

3.The butcher did not give any meat to the dog __________ .

4.From its experience, the dog found that ________.

5.At the end of the story, you'll find that _______.