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.

A year ago, I paid no attention to English idioms, though my teacher emphasized the importance again and again. But soon, the importance of English idioms was shown in an amusing experience.
One day, I happened to meet an Englishman on the road, and soon we began totalk. As I was talking about how I was studying English, the foreigner  seemed to be astonished gently shaking his head, shrugging his shoulders, saying, “You don’t say！”“You don’t say!” I was puzzled. I thought, perhaps this is not an appropriate topic. “Well, I’d better change the topic. ”So I said to him, “well, shall we talk about the Great Wall?” By the way, have you ever been there? “Certainly, everyone back home will laugh at me if I leave China without seeing it. It was magnificent.” He was deep in thought when I began to talk like a tourist guide, “The Great Wall is one of the wonders in the world. We are proud of it.” Soon I was interrupted again by his order “You don’t say!” I couldn’t help asking .I said, “Didn’t you say you don’t say?” Hearing this, the Englishman laughed to tears. He began to explain, “You don’t say actually means really? It is an expression of surprise. Perhaps you don’t pay attention to English idioms.” Only then did I had made a fool of myself. Since then I have been more careful with idiomatic expression.
1．A year ago, I paid no attention to English idioms because     .
A．English idioms were too difficult to master
B．I cared little about the teacher’s instruction
C．my teacher didn’t emphasize the importance
D．I had no interest in English learing
2．When I first heard “You don’t say!” I thought     .
A．the Englishman was not interested in my English
B．the Englishman was only interested in the Great Wall
C．I had talked too much
D．I had to stop talking at once
3．Which of the following is true?
A．The Englishman was leaving China without seeing the Great Wall.
B．The Englishman wanted to see the Great Wall after I talked about it.
C．The Englishman wanted me to act as his guide.
D．The Englishman visited the Great Wall and thought it worth visiting
4．After the Englishman explained the idiom,     .
A．the Englishman made me a fool
B．the Englishman made a fool of himself
C．I felt very silly
D．I felt proud of my understanding

Have you ever wondered why birds sing? Maybe you thought that they were just happy．After all, you probably sing or whistle when you are happy．
Some scientists believe that birds do sing some of the time just because they are happy．However, they sing most of the time for a very different reason．Their singing is actually a warning to other birds to stay out of their territory．
Do you know what a "territory" is? A territory is an area that an animal, usually the male, claims as its own ．Only he and his family are welcome there ．No other families of the same species are welcome．Your yard and house are your territory where only your family and friends are welcome．If a stranger should enter your territory and threaten you, you might shout．Probably this would be enough to frighten him away．
If so, you have actually scared the stranger away without having to fight him．A bird does the same thing．But he expects an outsider almost any time, especially at nesting （筑巢） season．So he's screaming （高声尖叫） all the time, whether he can see an outsider or not．This screaming is what we call a bird's song, and it is usually enough to keep an outsider away．
Birds sing loudest in the spring when they are trying to attract a mate and warn others not to enter the territory of theirs．You can see that birds have a language of their own．Most of it has something to do with attracting mates and setting up territories．
【小题1】Some scientists believe that most of the time birds' singing is actually

B
Everybody knows that words can carry messages. People communicate with words. Books, magazines, TV ， radio and films all help us to know what is going on in the world and what people are thinking about.
Do you think you can communicate without words? A smile on your face shows you are happy or friendly. Tears in your eyes tell others that you are sad. When you put up your hand in class, the teacher knows that you say something or ask a question. You shake your head, and people know you are saying “No”. You nod and people know you are saying “Yes”.
Other things can also carry messages. For example, a sign at the bus stop helps you to know which bus to take. A sign on the wall of your school helps you to find the library. Signs on doors tell you where to go in or out. Have you ever noticed there are a lot of signs around you and you receive messages from them all the time? People can communicate in many ways without words. For example, an artist can use his drawings to tell about beautiful mountains, seas and many other things.
66.Choose the best title for this passage.
A.Ways for Communication.
B.The Best Way for Communication.
C.The Only Way for Communication.
D.Words Can Carry Messages.
67.How can people communicate with each other?
A.With words only
B.Only without words.
C.Either with words or without words.
D.Just by using different kinds of signs.
68.Which of the following is NOT a way for communication without words?
A.A cry for help  B.A smile on your face   C.Making a face   D.Nodding your head
69.What does the road sign P tell people?
A.You can go into the park.           B.You can please everybody.
C.You can leave your car there.        D.You can cross the street there.
70.How can a musician (someone who writes music) communicate with people?
A.By saying something.                  B.By playing some music.
C.By writhing letters.                    D.All of the above are right.

Have you ever been to the beautiful country of Holland and its capital Amsterdam? Anyone who has traveled to Amsterdam would probably agree on one thing: Amsterdam’s story is a tale of two cities -- one during the day and a completely different one at night．
During the day, the largest city in the Netherlands sits quietly on the Amstel River．You can rent a bicycle, visit the Van Gogh or Anne Frank museum, or take a water taxi．But when the sun goes down, the partying begins．In the big clubs and in coffee shops, tourists gather to hang out, talk politics and smoke．
Several areas of the city clearly show the two worlds that rule Amsterdam．And they’re all within a short cab ride of each other．For example, Dam Square attracts daytime sightseers to its festivals, open markets, concerts and other events．Several beautiful and very popular hotels can be found there．And there’s the Royal Palace and the Magna Plaza shopping mall．
But at night party-seekers come to the square．Hip hop or funk music is heard there．．So if you come, be ready to dance．The clubs don’t shut down until 4 am．
And while you’re there, check out the various inexpensive ways to tour the city．Don’t worry about getting lost．Although Dutch is the official language, most people in Amsterdam speak English and are happy to help you with directions．And you’ll notice that half the people in the streets are on bicycles they rent．
Amsterdam also has a well-planned canal system．For about 10 dollars, you can use the canal bus or a water taxi to cruise（巡游） the "Venice of the North"．
The city has a historic past．One impressive place to visit is the Anne Frank House on Nine Streets．It was there that the young Jewish girl wrote her famous diary during World War II．Visitors can view Anne’s original diary and climb behind the bookcase to the room where she and her family hid from the Nazis for two years．
【小题1】What means of transport is not available to visitors in Amsterdam?