阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳答案。

    All living things need energy to live and grow. This energy comes first from the sun. Plants use water and sunlight to make their own food. Animals can not make their own food, and they eat plants. Other animals then eat the plant eaters.

    A food chain shows what eats what. It might show that zebras eat grass and then lions eat zebras.   

    Lions also eat other animals. Zebras eat other kinds of plants. So it takes more than one food chain to show how lions and zebras get their energy.

    A food web shows how food chains work together. From it we can see how energy moves from plants to animals.

    Plants and animals that live in hot, dry deserts depend on water as well as food. Creosote bushes have small leaves that hold water. Their seeds provide food and water for kangaroo rats. Kangaroo rats don't need to drink water. They get all the water they need from the plants they eat. Kangaroo rats keep cool by coming out only at night to look for food. Ringtail cats also come out only at night. Ringtail cats hunt and eat kangaroo rats. Coyotes eat both the kangaroo rats and the ringtail cats.

    Nothing is wasted in a food wed. Vultures eat dead animals. Vultures are scavengers. Scavengers do not hunt and kill other animals to get food. They eat animals that are already dead. When a ringtail cat or a coyote dies, it makes a meal for the vultures. Scavengers do an important job in keeping the environment clean.

    In most parts of the world, many students help their schools make less pollution．They join environment clubs．In an environment club, people work together to make our environment clean．

    Here are some things students often do．

    No-garbage lunches．How many lunch bags do you throw away after lunch? Environment clubs ask students to bring their lunches in bags that can be used again．Every week they will choose the classes that make the least garbage and report them to the whole school．

    No-car day．On a no-car day, nobody comes to school in a car including the students and the teachers．Cars give pollution to us, so remember:

    Walk, jump, bike, or run!

    Use your legs! It's lots of fun!

    Turn off the water! Do you know that some toilets can waste twenty to forty cubic meters of water an hour? In a year, that would fill in a small river. In the environment clubs, students mend those broken toilets．

    We love our environment．Let's work together to make it better．

    Zhalong is a nature park in Heilongjiang in Northeast China. It is one of the world's most important wetlands. The area provides food and homes for wildlife. It is an ideal home for different kinds of plants, fishes and birds.

    Many birds live comfortably in Zhalong Nature Park all year round, while some only stay for a short time. There are many fish in the wetlands, and the birds can easily catch them for food. Zhalong Nature Park is an important living area for the rare red-crowned cranes. There are not many red-crowned cranes in the world. Some of them live in Zhalong.

    Some people want to change the wetlands to make more space for farms and buildings. This means that there will be less and less space for wildlife.

    More and more birds are in danger because they do not have enough living space. Many of them died. The Chinese government wants to protect these endangered birds, and they can be safe in Zhalong.

    Every year a lot of tourists go to Zhalong to watch birds. This year members of our Bird Watching Club are going to study the different kinds of birds in Zhalong and the changes in their numbers. The study will begin next month.

    We do a bird count once a year. We are now inviting the second school students to help. We need more people to help us count and do something to help the birds. Many people do not understand the importance of the wetlands. We hope this information will help them understand it and make them actively take action to protect wildlife.

    We know people can be nice, but what about animals?

    Scientists say that some animals are capable(有能力的)of being nice. Animals that live in groups-like foxes, chimpanzees(大猩猩), and elephants-follow rules. They have to follow rules to get along and to survive(生存). However, animals can act nicely, even when they don't have to. Here are some surprising stories about animal behavior.

    Most people usually walk away when someone is unkind to them. Marc Bekoff, a researcher at the University of Colorado, saw a female(母的)red fox do just that. The female fox was unhappy because a male(公的)fox played roughly(粗鲁地)with her. When she walked away, the male fox showed her that he wanted to play nicely. He lowered his head and rolled on his back. The female fox gave him another chance, and this time, he played more gently.

    Geza Teleki is a scientist who studies chimpanzees in Tanzania. One day, Teleki hiked far away from his campsite. He didn't have any food. Teleki wanted some fruit from a tree, but the tree was too tall. A young chimpanzee watched him curiously as he tried to get something to eat. The chimpanzee climbed the tree, picked the fruit, and gave it to him!

    An elephant in Kenya hurt his trunk(象鼻子). He needed help because he couldn't put food into his mouth. Researcher Kayhan Ostovar watched silently. He saw the hurt elephant show his sore trunk to a healthy elephant. The healthy elephant didn't need any more information. He took a bush and put it carefully into his new friend's mouth.

    Hippos(河马)and crocodiles are usually good friends. They hang out together in rivers. But Karen Paolillo, a wildlife expert in Zimbabwe, saw something surprising. One day, a crocodile tried to eat a monkey that was next to a river. A hippo ran quickly to the crocodile and chased it away. Why did the hippo attack(攻击)the crocodile? Paolillo says hippos sometimes protect other animals from crocodiles.

Vision—phones(可视电话)

    Many inventions are very useful in our daily life. They have greatly changed our life. For example, radios, telephones and televisions are widely used in the world. When you turn on the radio, you can listen. But when you use the telephone, you can not only listen to others but also chat with them. However, you can't see anything at all. The television is much better than both of them. People can watch TV and listen to it, but they can't take part in what they see.

    Today, some people are using a type of telephone called the vision phone. With it two people can see each other when they are talking

    Vision-phones can be of great use when you have something to show the person when you are calling him or her. It may also have other uses in the future. Some day you may be able to call up a library and ask to read a book over your vision-phone. You may be able to do some shopping through it too. Perhaps in the future, the vision-phone will come into wide use in our everyday life.

    We all cry for water when we are thirsty. But do you know, in very hot, dry weather, plants also make very low sounds as if they are crying for help?

    You see, in a plant's stem there are several hundred "water pipes" that bring water from soil all the way up to the leaves. When the ground turns dry, it becomes harder and harder for plants to do this.

    In very hot days, plants have to get any water that they can get.

    Scientists Robot Winter has found out that when plants can get no water, their "water pipes" snap(发出声音). When that happens, the whole plant vibrates(颤动) a little.

    Robot knows that healthy, well-watered plants are quiet. He also knows that dry plants are many insects' favorites and they often attack(袭击) them. How do the insects know which are healthy plants and which are not? Robot thinks that the insects may hear the plants "crying" and they may come to kill them.