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.

    The world itself is becoming much smaller by using modern traffic and modern communication equipment(通讯设备). Life today is much easier than it was hundreds of years ago, but it has brought new problems. One of the biggest is pollution. To pollute means to make things dirty. Pollution comes in many ways. We see it, smell it, drink it and even hear it. Man has been polluting the earth. The more people, the more pollution. Many years ago, the problem was not so serious because there were not so many people. When the land was used up or the river was dirty in one place, people moved to another place. They are slowly polluting the whole world.

    Air pollution is still the most serious. It's bad for all living things in the world but it is not the only one kind of pollution. Water pollution kills our fish and pollutes our drinking water. Noise pollution makes us angry more easily.

Many countries are making rules to fight against pollution. They stop people from burning coal in houses and factories in the city, and from putting dirty smoke into the air.

Pollution by SO₂ is now the most dangerous kind of air pollution. It is caused by heavy traffic. It is sure that if there are fewer people driving, there will be less air pollution.

    The earth is our home. We must take care of it. That means keeping the land, water and air clean. And we must take care of the rise in population at the same time.

B

    Surtsey was born in 1963.Scientists saw the birth of this island. It began at 7.30 a.m. on 14th November. A fishing boat was near Iceland. The boat moved under the captain's（船长）feet. He noticed a strange smell. He saw some black smoke. A volcano（火山）was breaking out. Red-hot rocks, fire and smoke were rushing up from the bottom（底部）of the sea. The island grew quickly. It was 10 meters high the next day and 60 meters high on 18th November. Scientists flew there to watch. It was exciting. Smoke and fire were still rushing up. Pieces of red-hot rock were flying into the air and falling into the sea. The sea was boiling and there was a strange light in the sky. Surtsey grew and grew. Then it stopped in June 1967.It was 175 meters high and 2 kilometers long. And life was already coming to Surtsey. Plants grew. Birds came. Some scientists built a house. They want to learn about this young island. A new island is like a new world.

    A recently study found people's lives are made shorter in North China. It is showed the life expectancy(平均寿命) had been cut down by 5.5 years there. Researchers think that the heavy air pollution in China should be to blame. It's really the truth. Our government has already done something. However, it doesn't seem to work so well.

    “Air pollution in China is doing harm to people's health. The harm is much more serious than we can imagine,” said Chen Yuyu of Beijing University, one of researchers of this study.

    Dirty air brings serious problems in North China. In January this year, the air pollution was worse than that in other places. That was caused by rising temperature and waste gas from coal heating.

    Chinese government should strongly fight against air pollution. They should think of more proper ways to deal with the problem. People should be encouraged to take buses, ride bicycles or walk, instead of driving cars. The factories that pollute heavily should be closed.

    “We need to improve our environment, although it might be expensive. Protecting our environment means protecting ourselves,” Li Hongbin, another researcher of the study said.

    The world is not hungry, but it is thirsty. It seems strange that nearly 3/4 of the Earth is covered with water while we say we are short of（短缺）water. Why? Because about 97% of water on the Earth is sea water which we can't drink or use for watering plants directly(直接地）. Man can only drink and use the 3%-the water that comes from rivers and lakes. And we can't even use all of that, because some of it has been polluted(污染）.

    Now more water is needed. The problem is Can we avoid（避免）a serious water shortage later on? First, we should all learn how to save water. Secondly, we should find out the ways to reuse it. Scientists have always been researching in the field. Today, in most large cities water is used only once and then runs to the seas or rivers. But it can be used again. Even if(即使）every large city reused its water, there would not be enough. What can people turn to next?

    The seas seem to have the best answer. There is a lot of water in the seas. All that needs to be done is get the salt out of the sea water. This is expensive, but it's already used in many parts of the world. Scientists are trying to find a cheaper way of doing it. So you see, if we can find a way out, we'll be in no danger of drying up.

Why salmon will newer get lost

    When you're packing for an adventure, what's the most important thing you'll need? If you don't want to get lost, you' need a map. Or better yet, a GPS. What about other animals? How do they know where they're going?

    While humans depend on technology to travel, some animals have something far more advanced. Researchers, mainly from Oregon State University, US, found that Chinook salmon have a "built in GPS" of the Earth's magnetic field(磁场). This means as soon as they are born they are able to direct themselves in the ocean. It acts like a big map inside their brain.

    Scientists placed some baby salmon into a big swimming pool. To simulate the Earth's magnetic field, they put magnetic coils(线圈) all around the pool. Then, by changing the direction of the coils, the salmon began to change their own direction. They started to face in the direction of their ocean feeding area. This is a safe place in the ocean where salmon can find food to eat. When the scientists changed the coils to the opposite side, the salmon also turned in the opposite direction. Just by using their "built-in GPS", the salmon were able to figure out the direction of their feeding area.

    How did Chinook salmon get their "built in GPS"? The scientists believe that their navigation(导航) skills came through evolution(进化). The fish that were able to reach the feeding area lived longer. Then they could pass on their navigation skills to their babies. So if you're ever lost and in need of some help, maybe you should ask a salmon to point you in the right direction!