阅读理解

B

    Animals grow up in different ways. Some newborn animals are helpless but their mothers protect them. A newborn kangaroo is very small. It is only a few centimeters(cm) long. It closes its eyes and doesn't have hair. It stays safe in its mother' s pouch(育儿袋) for a long time.A newborn monkey can not walk. Its mother carries it everywhere.

Other baby animals can walk soon after they're born. They learn to run with their mothers when danger is near. A baby zebra can run, an hour after it is born.

    Some baby animals are born in a place that is safe. Baby wolves are usually born in big holes with little light. Other baby animals are born in the open. A baby elephant is often born on open land.

    Animals that drink their mothers' milk are called mammals. A mother bear's milk is rich. Baby bears have milk for a few months. This is the same with baby zebras. As baby animals grow, they need solid(固体) food. Baby lions eat what their mother can catch!

    Plants are very important living things. Life could not go on if there were no plants. This is because plants can make food from air, water and sunlight. Animals and men can't make food from air, water and sunlight. Animals get their food by eating plants and other animals. Therefore, animals and men need plants in order to live. This is the reason why we find so many plants around us.

    If you look carefully at the plants around you, you will find that there are many kinds of plants. Some plants are large while others are small. Most plants are green.

    Some plants have many small leaves. Others have only a few. There are many kinds of leaves. Leaves are of different shapes and colors.

    Leaves are also different in other ways. Some leaves have long thin parts at the end, we call them leaf stalks, some have short leaf stalks, others even have no leaf stalks. The leaf edges are also different. Some leaves have smooth(平滑) edges. Some have a wave-shaped edges. Others have edges like the teeth of a saw(锯子).

    Why don't birds get lost on their long flights (飞行) from one place to another? Scientists have studied this puzzle for a long time. Now they're starting to fill in the blanks(空白).

    Not long ago, experiments showed that birds use the sun to guide them during daylight hours. How do birds fly at night? Tests with artificial stars, which are made by people, have proved that certain night-flying birds are able to follow the stars in their long-distance flights.

    They found a bird that spent its lifetime in a cage and never flew under a natural sky. But it was born with the ability to use the stars to look for the direction. This bird's cage was placed under the sky filled with artificial stars. Any change in the position of the artificial stars caused a change in the direction of the bird's flight. From the experiment, they found that the bird tried to fly in the same direction as those artificial stars moving under the natural sky.

    But the stars are of course birds' main ways of navigation (航行), when the stars are hidden by clouds, they can still find their way by such landmarks (路标) as river courses, mountain ranges (山脉), coast lines and so on. Because of this ability, people use the dove (鸽子) to send messages in some fields. For example, the doves were used to send messages in both World War I and World War II. During that time, thousands of doves were used to carry important messages in order to save the lives of many thousands of people. So it is also the symbol of peace.

    But when it's too dark to see these things, the doves are not able to find their way. They only circle helplessly and get lost.

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    We each have memory(记忆力).That's why we can still remember things after a long time. Some people have very good memories and they can easily learn many things by heart, but some people can only remember things when they say or do them again and again. Many of the great men of the world have got surprising memories.

    A good memory is a good help in learning a language. Everybody learns his mother language when he is a small child. He hears the sounds, remember them and then he learns to speak. Some children are living with their parents in foreign countries. They can learn two languages as easily as one because they hear, remember and speak two languages every day. In school it is not easy to learn a foreign language because the students have so little time for it, and they are busy with other subjects, too. But your memory will become better and better when you do more and more exercise.

    The unknown world's mystery

    The sea is the biggest unknown part of our world. It covers about seventy-one percent of the earth. There is still much to be discovered about this huge part of water. If the waters of the ocean could be removed, the sea floor with its wide valleys(峡谷), tail mountains and long rivers in the sea would be a special sight.

    Tourism under the deep blue sea

    From tourist submarines(潜艇) to underwater dining, undersea tourism is making a big splash.

    Tourists can now explore(探索) the world under the sea without ever getting wet.

    Tourist submarines

    The popularity of submarine tours has grown fast during these years. Now, submarine tours have been on in more than 20 places worldwide, including the waters around Okinawa and Taiwan's Green Island. The submarines carry nearly 2 million tourists each year. Large windows give passengers special views as the submarines explore colorful coral reefs and sunken ships. Most one-hour tours cost about $ 80.

    Underwater dining

    For a more fantastic experience, tourists can enjoy fine dining under the sea. In 2016 the Hilton Maldives Resort & Spa opened the world's first underwater restaurant, Ithaa. Tourists walk down a staircase into the restaurant, which rests 35 feet in the Indian Ocean. You can have a great ocean view. But this excellent view doesn't come cheap. The dinner costs about $ 400 per person. Be sure to book it early, too, The restaurant seats only 14 people.

    You and I can tell one face from another easily, but can computers do the same with few mistakes? At an earlier time, many thought it was impossible, but progress in facial recognition(识别)software has made it come true. Technology is quickly catching up with the human ability to read faces.

    Some facial recognition systems use a digital picture and measure(测量) different points on the face. Measurements include the distance between the eyes, the width of the nose, the length of the jaw(下巴) line and more. A detailed map, or faceprint, of the face is developed, stored and later used as a basis for comparison and matching.

    Some government agencies, airports and banks use facial recognition technology for safety purposes. Apple and Facebook use it to provide their users with added convenience. For example, Apple's new iPhone is expected to use it to unlock the home screen. Other companies use it to help them in better recognizing their customers' needs. For example, some stores are checking into the use of the technology to catch sight of return customers. Then they can offer special deals, based on the customers' buying habits.

    In America, facial recognition is used by universities to check students' attendance. This year Welsh police used it to catch a terrorist outside a football game. In China it checks on the identities of ride-hailing drivers, permits tourists to enter some places of interest quickly and lets people pay for things with a smile.

    While some systems are used with the knowledge of the persons, others aren't, and that raises worries. For many people, however, convenience outbalances the worries, in other words, meaning that facial recognition technology is likely here to stay.