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2024年6月17日发(作者：资源库网站源码)
HOW LIFE BEGAN ON THE EARTH
地球上生命的起源
No one knows exactly how the earth began, as it happened so long ago.
However, according to a widely accepted theory, the universe began with a "Big
Bang" that threw matter in all that, atoms began to form and
combine to create stars and other bodies.
没有人确切知道地球是怎么样开始形成的，因为在很早很在以前地球就形成了。然而，
一种普遍为人们所接受的理论是：宇宙起源于一次大爆炸，这次大爆炸将物质投射到四面
八方。然后，原子开始形成并结合成恒星和其他天体。
For several billion years after the "Big Bang", the earth was still just a cloud of
dust. What it was to become was uncertain until between 4.5 and 3.8 billion years
ago when the dust settled into a solid globe. The earth became so violent that it
was not clear whether the shape would last or not. It exploded loudly with fire and
rock. They were in time to produce carbon, nitrogen, water vapour and other gases,
which were to make the earths atmosphere. What is even more important is that
as the earth cooled down, water began to appear on its surface.大爆炸后好几十亿年
过去了，但地球还只是一团尘埃。随后它会变成什么没人能知道，直到38-45 亿年前，这
团尘埃才慢慢地形成一个团体的球状物。地球开始变得激烈动荡，不知道这个固体形状是
否会继续存下去。它猛烈地爆炸喷出了烈火与岩石，最终产生了碳，氮气，水蒸气和其他
多种气体，从而形成了地球的大气层。更为重要的是，地球冷却了下来，地球的表面就开
始出现了水。
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Water had also appeared on other planets like Mars but, unlike the earth, it
had disappeared later. It was not immediately obvious that water was to be
fundamental to the development of life. What many scientists believe is that the
continued presence of water allowed the earth to dissolve harmful gases and acids
into the oceans and seas. This produced a chain reaction, which made it possible
for life to develop.在火星这些其他行星上都出现了水，但和地球不同的是，这些水后来
都消失了。水对于生命的发展会起关键作用，这一点在当时并不明显。很多科学家相信，
由于地球上长期有水存在，使得地球得以把有害气体和酸性物质溶解在海洋里。这就产生
了一系列的反应，使得生命就有可能开始发展了。
Many millions of years later, the first extremely small plants began to appear
on the surface of the water. They multiplied and filled the oceans and seas with
oxygen, which encouraged the later development of early shellfish and all sorts of
fish. Next, green plants began to grow on land. They were followed in time by land
animals. Some were insects. Others, called amphibians, were able to live on land as
well as in the water. Later when the plants grew into forests, reptiles appeared for
the first time. They produced young enerally by laying eggs. After that, some huge
animals, called dinosaurs, developed. They laid eggs too and existed on the earth
for more than 140 million years. However,65 million years ago the age of the
dinosaurs ended. Why they suddenly disappeared still remains a mystery. This
disappearance made possible the rise of mammals on the earth. These animals
were different from all life forms in the past, because they gave birth to young
baby animals and produced milk to feed them.
好几百万年后，水的表面开始出现了极小的植物。他们繁殖起来就使得早期的海洋充
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