A

    Many people think the camel stores water in its hump (驼峰), but it does not. Instead, the camel stores something else there—food. The camel's hump is really a hump of fat (脂肪). The camel is often called "a ship of the desert". When the camel is not travelling and is in a place where there is much food and water, it eats and drinks a lot. As it does so, its hump rises from the fat its body makes. Then, when the camel is travelling through the desert and when there is no food, it can live off the stored fat.

    A camel can go on for days or weeks with little food or water. However, when its hunger reaches the starvation (饿死)point, its hump shrinks (收缩) and may even slip off its back and hang down its side.

    Camels are not fussy (挑剔的) about what they eat. Thorny (多刺的) plants don't hurt their mouths, grass of any kind will do and so will hay, dry grain and cactuses (干草, 干粮, 仙人掌).

There are one­ hump camels and two­ hump camels. Camels with one hump are called Arabian camels. They come from North Africa. Camels with two humps are from Asia.

    Let me tell you something about sharks. Sharks are among the oldest animals in the world. There are over three hundred and fifty different kinds of sharks in the world. Most sharks are about two meters long and live in the seas.

    A shark can smell something in the water, for example, the blood of animals. That helps them find their food. Sharks mainly eat fish, other sharks and plants in the sea.

    Most sharks bite people by mistake. They think a person is a large sea animal. When the sun goes down or comes up, sharks are looking for food. So at these times people shouldn't go swimming in the sea.

    Today people kill sharks for food and their skin. The number of sharks in the world is dropping fast.

E

    Artificial intelligence（人工智能）, or AI in short, is the science of giving computers and machines ability to think and work like humans. AI scientists and engineers have made a lot of cool technologies.

    AI is rapidly catching up with the human ability to read faces. As a result, facial recognition（识别）is used a lot in the world. Chinese police use this technology to identify criminals（罪犯）.Once they caught a criminal when he attended a concert. It also checks the ID of ride-hailing（网约车）drivers and lets people pay for things with a smile.

    AI is also used in self-driving cars, which are believed to be the future of driving. Most drivers may wave or nod at passers-by to let them cross the street, but self-driving cars don't have this ability. Carmakers are testing a light signal system to help them "speak" to humans. The system can show what self-driving cars will do. For example, if a driverless car is yielding（让路）, it will flash two white lights side to side. A rapidly flashing light tells passers-by that the car is about to speed up.

    Service Robots also show you know powerful AI is. Imagine this—you come back home from school and your robot housekeeper is waiting for you at the door. After dinner, he teaches you to play the piano, just like a real music teacher. Such thoughts will soon happen in the real world. In the future, more and more service robots will become good home helpers.

    AI is so powerful that it can help human beings and even replace us in many jobs.

    Squirrels (松鼠) are getting ready for winter. They are looking for nuts and seeds, digging holes in the ground or finding holes in trees. That's where they store the food they will need during the coming months, when the weather is cold and sometimes snowy.

    Squirrels spend a lot of time in trees, which are like restaurants for them. Among their favorite things to eat are nuts and other parts of trees, like tender buds (花苞).

    Squirrels may also eat corn, insects and other animals. And, as anyone who has a bird knows, squirrels love bird food!

    Squirrels stay active all winter, so they need plenty of food to help keep up their energy. Squirrels tend to bury food underground, piece by piece. Some squirrels may gather food into piles that they put at the base of trees or bury underground.

    When they need food, squirrels use their memory and smell to help them find what they buried. Sometimes, you'll even see them digging through the snow.

    Squirrels make nests in trees. Some squirrels spend much of the winter in underground tunnels (地道), where it is warmer.

    When spring comes, squirrels change their eating habits to new plant growth, like buds and leaves. Sometimes they forget to dig up all their buried nuts.

    That's why you'll sometimes find a little tree growing in a place where neither you nor your family planted it. It must have been the squirrels.