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我们有幸生活在生命的乐园——地球。这里不仅有适于生物生存和繁衍的条件,还有四季的变化。春季万紫千红,繁花似锦;秋季红叶簇簇,硕果累累;夏天可以下水游泳,搏击风浪;冬天能挑战严寒,溜冰滑雪。为什么在地球上的一些地方,一年之中会发生温度的周期性变化呢?地球围绕太阳运转的轨道不是正圆,而是椭圆形。有时地球离太阳近一些,有时远一些。会不会是地球与太阳距离的变化造成四
We have the privilege of living in the paradise of life - the earth. Not only are there conditions suitable for living and reproducing creatures, but there are also changes in the four seasons. The spring is full of colorful flowers. The autumn leaves are clustered with fruitful results. You can swim in the summer and fight against the storm. In the winter, you can challenge the cold and skate. Why do periodic changes in temperature happen in one year in some places on Earth? The orbit around the sun is not a perfect circle but an ellipse. Sometimes the earth is closer to the sun and sometimes farther away. Will it be caused by changes in the distance between the Earth and the Sun?