1. The earth spins round once every twenty-four hours.
    地球每二十四小时自转一周。

2. This happens to most parts of the earth every twenty-four hours. 2
    地球上的大部分地区的二十四小时都是如此。

3. The more the rays are spread out, the less heat they give to the part of the earth they touch.
    但光线越扩散，它给予照射地区的热量就越少。

4. Through the ages the earth has cooled.
    随着时间的推移，地球冷却下来了。

5. The whole journey of the moon round the earth takes twenty-eight days.
    月亮绕地球旋转一周需要二十八天。

6. The white clouds above the Earth add beauty to the picture.
    地球上空漂浮的白云使这幅画变得更美了。

7. The blue water in the oceans and seas of the Earth makes a dramatic image.
    地球上大洋大海里的蔚蓝色的水构成了一幅激动人心的图画。

8. The rise of acquired immune deficiency syndrome (AIDS) around the earth has represented a major challenge to medical progress both in developed and in less — developed countries.
    全球艾滋病的蔓延无论在发达国家还是在欠发达国家都是对医学进步的重大挑战。

9. The Earth was formed about five billion years ago from a rotating, circular cloud of dust and gases such as hydrogen and nitrogen.
    地球的形成约在50亿年前，起源于一团循环旋转的尘埃和诸如氢、氧之类的气体。

10. The first animals on this living sphere, the Earth, were primitive marine animals, and then around 500 million years ago these sea animals developed shells.
    在地球这个有生命的星球上，最早的动物是原始海洋动物。后来，在大约5亿年前，这些海洋动物进化成甲壳动物。