1970 was "World Conservation Year". The UN wanted everyone to know that the world was in danger - they hoped that governments would act quickly in order to conserve nature. Here is one example of the problem. At one time there were 1,300 different plants, trees and flowers in Holland, but now only remain 860. The others have been destroyed by modern man and his technology. We are changing the earth, the air and the water, and everything that grows and lives here. We can't live without these things. If it continues like this, we shall destroy ourselves.

       What will happen in the future? Perhaps it is more important to ask "What must we do now?" The people who will be living in the world of tomorrow are the young of today. A lot of them know that conservation is necessary. Many are helping to save our world. They plant trees, build bridges across rivers in forests, and so on. In a small town in the United States a large group of girls cleaned the banks of 11 kilometers of their river. Young people may hear about conservation through a record called NO ONE'S GOING TO CHANGE OUR WORLD. It was made by the Beatles and other singers. The money from it will help to conserve wild animals.

     We often read the Air Quality Index （空气质量指标） or AQI reported in the newspaper. The AQI helps us understand what the air quality around us means to our health. The AQI uses colors, numbers and words to tell us about the air. Let's see what these colors and numbers mean.

    There are some easy things you can do to protect the environment and the earth. Choose ideas from the list or come up with a few of your own.

    ·Plant flowers, grass or trees.

    ·Whenever you visit a park or beach, take away what you bring there-keep rubbish in a bag until you can put it in a dustbin.

    ·Turn off the lights, TV sets when you leave the room. This saves a lot of electricity.

    ·Turn off the tap when you brush your teeth. You can save some water by not letting it run. Also, use a glass cup instead of a paper cup because this saves paper.

    ·Keep the doors and windows closed in winter to keep cold air in.

    ·Give your old books and magazines to a library instead of throwing them away.

    ·Give your old clothes to poor children you know instead of throwing them away.

    ·Use both sides of paper.

    ·Stop pouring dirty water into the rivers or lakes nearby.

    ·Encourage all your friends to do the same things you do to help protect the earth.

    You don't have to wait until Earth Day to do these things. Make every day Earth Day.

    If everyone makes a contribution to protecting the environment, the world will become much more beautiful.

    From a plane we can see the fields, cities, mountains or seas below. If we go into space, we see more and more of the Earth. People and man-made satellites have been sent out into space to observe the Earth carefully and people have learnt mire about the Earth in the last few years.

    The sea looks very beautiful when the Sun is shining on it. But it can be very terrible when there is a strong wind.

    The sea is very huge. It nearly covers three quarters of the Earth. The sea is also very deep in some places. There is one place where the sea is about 11 kilometers in depth. The highest mountain is the world is about 9 kilometers high. If that mountain was put into the sea at that place, there would be still 2 kilometers of water above it!

    In most parts of the sea, there are many kinds of fishes and plants. Some live near the top of the sea. Others live deep down. There are also a lot of small living things, and quantities of fishes live by eating them.

    The sea can be very cold. When people go down, the sea becomes colder and colder. Only some men could go down into the deep sea at first. But in 1970, five women scientists lived in the deep sea for fourteen days.