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    After a long day's study at school, you are very tired. So after school you go home to relax. When you get home, a robot greets you. He's happy to see you and helps you take your school things to your room. He listens to you talk about your school life and tells you a new joke. And he tells you to call your cousin and to say happy birthday. And then he helps you with your homework.

    This is your future, and the robot's name is NAO. NAO has a small body, big eyes and a large head. He can walk and dance. He listens and talks, and he even learns and thinks for himself. His creators(创造者) predict that the robot will be in people's homes before 2040.

    This $16,000 robot knows who you are. NAO can even express emotions(表达情感). He is a self-guided robot. A self-guided robot can sense(感觉), think and act. Other robots might do two out of the three. For example, a robot might sense things using cameras and think using computers, but with no arms, he can't act. Another robot can move and sense things, but he can't think for himself. These aren't self-guided robots. But NAO can do them all.

    Apple has created a new robot named Daisy that can break a dead iPhone into pieces and find out valuable materials such as silver and tungsten (钨) in order to protect the environment.

    The robot can break up a dead phone in just 18 seconds and is a new type for Liam, another recycling robot Apple announced in 2016. Liam had 29 arms and could break iPhone into pieces within just 11 seconds.

    Daisy is able to break up 9 kinds of the iPhone, grouping them into usable parts. And it can find out valuable materials that traditional robots can't do.

    Without being stopped. Daisy is likely to do with over 1 million phones per year, a small part of the more than 2017 million phones Apple sold in 2017. The machine is programmed to carefully break up the many pieces of returned iPhones, including SIM card plates, batteries and cameras.

    It does this by taking away different parts of the iPhone bit by bit so they are all easier to recycle, separating out the valuable silver, tungsten and other parts. Computers made by other companies seem to be easier to break up. However. Apple does not make it public how many of its dead phones are recycled every year.

    In today's world, almost everyone knows that air pollution and water pollution are harmful to people's health. However, not all the people know that noise is also a kind of pollution, and that is harmful to human health, too.

    People who work and live under noisy conditions usually become deaf. Today, scientists believe that 10% of the workers in Britain are becoming deaf because of the noise where they work. Many of the workers who print newspapers and who weave cloth (织布) become deaf. Plenty of people living near airports also become deaf. Recently it was discovered that many teenagers in America could hear no better than 65-year-old persons, because these young people like to listen to pop music and most of pop music is a kind of noise. Besides, noise which is produced by jet planes or machines will make people's life difficult and unpleasant. It can make people ill or even drive them mad.

    It is said that a continuous noise of more than 85 decibels (分贝) can cause deafness. Now the governments in many countries have made laws to control noise and make it less than 85 decibels.

    In China, the government is trying to solve not only air and water pollution problems but also noise pollution problems.

    In many places the weather changes during the year. These changes are called seasons. In the north and south there are four seasons in a year. At the North and South Pole, there are only two seasons. In tropical (热带) places near the Earth's equator (赤道), there are two seasons: a 'wet' season and a 'dry' season. Each season brings changes. They are important for plants and animals that live in different parts of the world.

    Spring starts when the day and night are the same length. The weather gets warmer and sunnier. Trees and plants start to grow. Many animals have their babies in spring.

    Summer begins on the longest day of the year. In the north this is on June 21 or 22. Summer is usually the warmest and sunniest time of the year. Fruit grows faster on trees and plants. Young animals grow bigger and stronger.

    Autumn starts when the day and night are the same length again.

During autumn, the leaves change color and fall down from the trees. Some animals collect food before winter comes.

    Winter begins on the shortest day of the year. In the north this is on December 21 or 22. The weather is colder and in some places there is lots of snow. Plants and trees stop growing. Some animals, like bats and bears, find places to hide and sleep. This is called hibernation.