1. Because of water, Earth is a living planet.
    因为有水，地球才成了一个有生命的行星；

2. By 1989, almost every nation on earth had established a program educating its people about AIDS, according to Jonathan Mann, director of the World Health Organization's (WHO) International Program on AIDS.
    据世界卫生组织国际艾滋病项目主任乔纳森·曼说，到1989年几乎每个国家都制订了对公民进行艾滋病教育的计划。

3. By measuring how closely current populations are related, the authors trace the routes by which early humans migrated around the earth.
    通过测定当前人类种群间的亲缘关系，作者们弄清了地球上早期人类迁移的路线。

4. We can either dig out some earth worms in my yard or buy some shrimps in the market.
    我们可以到我家院子里 挖一些蚯蚓,或者在市场上买一些小虾.

5. It is quite reasonable to regard the sea floor as the basic form of the crust of the earth, with, superimposed upon, it the continents, together with the islands and other features of the oceans.
    因此完全有理由把海床看作地壳的基本模壳，上面附加着大陆以及岛屿和海洋的其他形态。

6. It requires 97 per cent less energy to travel the quarter of a million miles from the Moon to Earth-orbit than the 200 mile-journey from Earth´s surface into orbit!
    因此，从月球到地球的25万英里所消耗的能量要比从地球表面进入地球轨道的200英里所耗能量少97%。

7. It takes much less energy to accelerate to that 1.5 miles per second than it does on Earth.
    在月球上加速到每秒1.5英里比在地球上所用能源要少得多。

8. When our part of the earth faces the sun, we see sunlight and have day.
    我们这半球面对太阳时，我们能看到阳光，这时是白昼。

9. When the north pole is towards the sun, the sun´s rays shine down quite straight on the northern part of the earth, while they slant down towards the southern part.
    北极斜向太阳时，阳光直射在北半球，斜射在南半球。

10. Without the air to stop some of the sun´s heat, every part of the earth would be burning hot when the sun´s rays strike it.
    假如没有空气吸收太阳的一些热量，地球在阳光照射下就会灼热不堪。