【正文】
。 。 。 。 五 閱讀 : How life began on the earth? After the “Big Bang(宇宙大爆炸 )”,the earth was just a cloud of energeticdust. What it was to bee was a mystery until the dust began to slowly bine into a ball moving around the sun. The problem was that the earth became violent because it was not clear whether the solid shape was to last or exploded loudly with fire and rock,which were in time to produce the water vapour,carbon dioxide,oxygen,nitrogen and other gases, which were to make the earth’s the earth cooled down,water began to appear on its knew that it was going to be different from other plas going round the had already disappeared from plas like Mars or satellites like the moon,but it stayed on the earth. This is how the earth began to show its special people think that this was important for the beginning of life. It allowed the earth to dissolve harmful gases, which had bee part of the earth’s atmosphere,into the oceans and made it possible for life to begin to develop. What scientists think is that the earth was different because of the arrival of small plants growing in the water on its understood that these plants were the start of many multiplied and filled the first oceans and seas with oxygen .This encouraged the development of early shellfish and all sorts of fish. Many millions of years later the first green plants began to appear on believe that taking carbon dioxide from the atmosphere and filling the air with oxygen helped life to land animals were ,called amphibians,were able to live on land as well as in the the plants grew into forests,reptiles appeared for the first produced young generally by laying ,some huge animals,called dinosaurs,developed,They laid eggs too. They became the most important animals on the earth for millions of years. But when they disappeared,mammals became more were the last group of animals and they were different because they produced their young from whithin their bodies. Small clever animals,now with hands and feet,appeared and spread all over the developed new methods of growing food,hunting and moving time went by they covered the earth and have bee the most important animals on the they are not taking care of the earth very are putting too much carbon dioxide into the atmosphere,which prevents heat from escaping from the earth into earth may bee too hot for the lives on life will continue on the earth for millions of years to e will depend on whethe