1. The twentieth century began with powerful countries competing to take advantage of the Earth.
    从20世纪初起，各强国竞相利用地球资源。

2. These mysterious patches of light are still visible today and so bright that they have been seen from U.S. spacecraft in orbit around the earth.
    这些神奇的光带如今仍然可见，而且明亮得连在绕地球轨道飞行的美国飞船里都可以看到。

3. Then too, the triangle is one of only two places on earth where a compass needle points to true north rather than magnetic north, causing problems in navigation.
    除此之外，此三角是地球上惟一的两个罗盘指针指向真正北方而不是磁极北方的地段之一，这就造成了航行上的麻烦。

4. Now the slanting rays cover a much larger surface of the earth than the same number of rays coming straight down.
    此时，斜射的光线要比同样数量的直射的阳光在地表的照射面积大。

5. Now that they are no longer ignorant of the causes of the sickness of our planet, they seek ways to help the Earth, to give back what they take away.
    由于不再无视地球罹难的根源，人们正在寻求各种方法来治疗它，把自己取走的东西归还给地球。

6. Now everyone must protect planet Earth, a planet in danger.
    如今人人必须保护地球，保护这个身处险境的星球。

7. No one on earth ever had a greater chance for glory.
    世界上再没有什么人有过比此更大的争取荣耀的机会了。

8. Housing developments and shopping centers cover much of the Earth with paved and concrete surfaces.
    住宅区和购物中心使地球上许多地方的表面都铺上了混凝土。

9. Do you really believe in the existence of God?
    你真地相信上帝存在吗?

10. Despite their short time on Earth, however, people have brought about enormous changes to the surface of the planet — changes far out of proportion to the interval of time they have occupied it.
    然而，尽管在地球上的时日尚短，人类却已给地球表面带来了巨大的变化——这些变化与人类占据地球的短暂时间相比，是远远不成比例的。