Question

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.

Brief1.	People living in a particular2.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 mainly3.in biology and history.
Biology reasons	The amount of melanin, by which a person’s skin color is 4.varies from people to people. The more melanin a person has, the 5.his or her skin will be. Vitamin D is another source 6.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 hioknj006Dad 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 7.vitamin D, their skin color became lighter. Generally speaking, people in areas with strong sunlight, have darker skin 8.people in other areas have lighter skin.
9.	Melanin 10.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.

Answer

1.introduction

2.areas

3.lie

4.determined

5.darker

6.affecting

7.produce

8.while

9.conclusion

10.plays

【解析】

这一篇说明文。短文从生物学和历史两个方面介绍了为什么会有各种不同的肤色。

1.

考查获取信息、提取信息和处理信息的能力。根据第一段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. 你有没有想过为什么世界上有那么多肤色？你知道为什么生活在特定地区的人通常有某种颜色吗？生物学和历史是造成这种情况的两个原因。 所以本空在作简短的介绍。置于形容词之后用名词。 故填introduction。

2.

考查获取信息、提取信息和处理信息的能力。根据第一段第Do you know why people living in particular areas usually have a certain color? 你知道为什么生活在特定地区的人通常有某种颜色吗？本句为原则再现。置于形容词后所以填名词复数。故填areas。

3.

考查获取信息、提取信息和处理信息的能力。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。故填lie。

4.

考查获取信息、提取信息和处理信息的能力。根据第二段Skin contains something called melanin, which determines a person’s skin color.可知，皮肤含有一种叫做黑色素的物质，它决定一个人的肤色。一个人的皮肤是由黑色素决定的，本句为被动语态。故填determined。

5.

考查获取信息、提取信息和处理信息的能力。根据第二段The more melanin a person has, the darker his or her skin will be.可知，一个人的黑色素越多，他或她的皮肤就会越黑。本句为原词复现。故填darker。

6.

考查获取信息、提取信息和处理信息的能力。根据第三段第一句Skin color is also affected by another source ---- vitamin D.可知，皮肤颜色也会受到另一种来源——维生素D的影响。本句转换成现在分词短语修饰another source。故填affecting。

7.

考查获取信息、提取信息和处理信息的能力。根据第四段第四行they could get enough sunlight to produce vitamin D. 他们可以获得足够的阳光来产生维生素D。本句为动词不定式后接动词原形。故填produce。

8.

考查获取信息、提取信息和处理信息的能力。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. 现在，生活在像非洲这样阳光强烈地区的人，皮肤颜色更深，而生活在其他地区的人皮肤颜色更浅。本句为原词复现。 故填while。

9.

考查获取信息、提取信息和处理信息的能力。根据最后一段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. 可知，进化给了我们五彩缤纷的肤色。人类一直有黑色素来决定我们的肤色。历史改变的是我们生活的环境。这反过来又改变了我们的黑色素生成，并最终改变了肤色。所以最后段是对短文的总结。故填conclusion。

10.

考查获取信息、提取信息和处理信息的能力。根据最后一段Humans have always had melanin to determine our skin color. 可知，人类一直有黑色素来决定我们的肤色。所以黑色素在决定我们皮肤的颜色时，扮演着重要的角色。play a part/role in,主语是不可数名词Melanin，故用单数形式。故填plays。