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Have you ever wondered why there are so ...

Have you ever wondered why there are so many skin colors in the world? Do you know why people living in particular areas usually have a certain color? Biology and history are the two reasons for this.

Skin contains something called melanin, which determines a person’s skin color. The more melanin a person has, the darker his or her skin will be. The amount of and the production of melanin are controlled by genetics, but can be affected by other things, such as sunlight. If a person lives in a place with less sunlight, a person’s body will produce less melanin, making the skin lighter.

Skin color is also affected by another source ---- vitamin D. humans all need vitamin D to build bones. People can get it by eating foods such as fish and milk, or from sunlight, so sunlight absorbed by melanin cannot be used for vitamin D production. Therefore, a dark—skinned person will produce less vitamin D than a light—skinned person when they received the same amount of sunlight.

The connection between vitamin D production and skin color is clear when we look at evolution. The earliest humans lived in Africa, their dark skin produced less vitamin D because of their dark skin. As a result, their skin made less melanin, so they could get enough sunlight to produce vitamin D. their skin gradually got lighter and they lost hair. Now, people living in areas with strong sunlight like Africa, have darker skin, while people living in other areas have lighter skin. The exception to this is the Inuit, who live in a place with little sunlight, but have dark skin because they eat a lot of fish and have enough vitamin D.

Evolution has given us a rainbow of skin colors. Humans have always had melanin to determine our skin color. What has changed through history is the environment where we have lived. This has in turn changed our melanin production, and eventually, skin color.

Brief __71__

People living in a particular __72__ usually have the same skin color and there are

many different skin colors in the world.

Reason for skin  color

The reasons for different skin colors mainly__73__ in biology and history.

Biology reasons

  The amount of melanin, by which a person’s skin color is__74__ , varies from people to people. The more melanin a person has, the __75__ his or her skin will be.

Vitamin D is another source__76__ skin color. Vitamin D is necessary for humans to

build bones. Sunlight contributes to vitamin D in the skin.

Historical                            

reasons

The earliest people in Africa had dark skin with hair covering it because the sunlight is very strong.

When they moved to places where they could not get enough sunlight to__77__

vitamin D, their skin color became lighter.

Generally speaking, people in areas with strong sunlight, have darker skin __78__ people in other areas have lighter skin.

 __79__

Melanin__80__an important role in our skin color. With our living environment changing, melanin production is changed, which leads to the changes in our skin color.

 

 Introduction  area  lie  determined  darker  affecting  produce  while  conclusion  plays 【解析】 试题分析: Introduction     归纳总结题。归纳全文是关于为什么会有各种不同的肤色的原因。  area       原词再现。根据第一段第2行in particular areas。  lie    同义句转换。根据第一段最后一句Biology and history are the two reasons for this.说明肤色不同是因为生物学和遗传,故转换成原因在于lie in   determined    句式转换。根据第二段第一行which determines a person’s skin color,把这个主动句变成了被动形式。  darker  原词再现。根据第二段1,2行The more melanin a person has, the darker his or her skin will be.  affecting      同义句转换。根据第三段第一句Skin color is also affected by another source ---- vitamin D.转换成现在分词短语修饰another source。  produce   原词再现。根据第四段第四行they could get enough sunlight to produce vitamin D. their skin gradually got lighter and they lost hair.  while     原词再现。根据第四段Now, people living in areas with strong sunlight like Africa, have darker skin, while people living in other areas have lighter skin.  conclusion    归纳总结。Conclusions就是上文得到的最后的结论。  plays  固定词组。Play a part/role in…主语是不可数名词Melanin,故用单数形式。 考点:考查任务型阅读
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Honey from the African forest is not only a kind of natural sugar, it is also delicious. Most people and many animals like eating it. However, the only way for them to get that honey is to find a wild bees' nest and take the honey from it. Often, these nests are high up in trees, and it is difficult to find them. In parts of Africa, though, people and animals looking for honey have a strange and unexpected helper - a little bird called a honey guide.

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Scientists do not know why the honey guide likes eating the wax, but it is very determined(坚定的) in its efforts to get it. The birds seem to be able to smell wax from a long distance away. They will quickly arrive whenever a beekeeper is taking honey from his beehives, and will even enter churches when beeswax candles are being lit.

1.Why is it difficult to find a wild bees' nest?

A.It's small in size.

B.It's hidden in trees.

C.It's covered with wax.

D.It's hard to recognize.

2.What do the words "the follower" in Paragraph 2 refer to?

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3.The honey guide is special in the way              .

A.it gets its food

B.it goes to church

C.it sings in the forest

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B.Wax and Honey

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On a hill 600 feet above the surrounding land, we watch the lines of rain move across the scene, the moon rise over the hills, and the stars appear in the sky. The views invite a long look from a comfortable chair in front of the wooden house.

Every window in our wooden house has a view, and the forest and lakes seldom look the same as the hour before. Each look reminds us where we are.

There is space for our three boys to play outside, to shoot arrows, collect tree seeds, build earth houses and climb trees.

Our kids have learned the names of the trees, and with the names have come familiarity and appreciation. As they tell all who show even a passing interest, maple(枫树)makes the best fighting sticks and white pines are the best climbing trees.

The air is clean and fresh. The water from the well has a pleasant taste, and it is perhaps the healthiest water our kids will ever drink. Though they have one glass a day of juice and the rest is water, they never say anything against that.

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D.The lakes outside the windows are quite different in color.

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B.The seasons make the scenes change.

C.The weather often changes in the forest.

D.The door is a good position to enjoy changing seasons.

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B.To introduce her children’s happy life in the forest.

C.To show that living in the forest is healthful.

D.To share the joy of living in the nature.

 

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One of the greatest contributions to the first Oxford English Dictionary was also one of its most unusual. In 1879, Oxford University in England asked Prof. James Murray to serve as editor for what was to be the most ambitious dictionary in the history of the English language. It would include every English word possible and would give not only the definition but also the history of the word and quotations (引文) showing how it was used.

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Minor joined the army of volunteers sending words and quotations to Murray. Over the next years, he became one of the staff's most valued contributors.

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B.He sent newspapers, magazines and books to Murray.

C.He provided a great number of words and quotations.

D.He went to England to work with Murray.

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1.A While               B. After               C. Before              D. Until

2.

A.time

B.then

C.here

D.there

 

3.

A.began

B.enjoyed

C.kept

D.stopped

 

4.

A.behind

B.over

C.in front of

D.beside

 

5.

A.pretending

B.seen

C.prepared

D.hold

 

6.

A.frightened

B.surprised

C.puzzled

D.pleased

 

7.

A.treated

B.welcomed

C.received

D.known

 

8.

A.around

B.up

C.in

D.out

 

9.

A.another

B.all

C.any

D.each

 

10.

A.able

B.about

C.willing

D.anxious

 

11.

A.told

B.showed

C.asked

D.gave

 

12.

A.last

B.first

C.least

D.once

 

13.

A.insisted

B.apologized

C.wondered

D.regretted

 

14.

A.Certainly

B.Really

C.Why

D.How

 

15.

A.knew

B.found

C.explain

D.thought

 

16.

A.strange

B.famous

C.wanted

D.curious

 

17.

A.for

B.at

C.after

D.like

 

18.

A.believe

B.agree

C.remember

D.learn

 

19.

A.necessary

B.funny

C.lucky

D.clear

 

20.

A.need

B.will

C.can

D.might

 

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