英国学生科学读本 第80期:我们脚下的土地(1)

 　　Lesson 80 The Soil Beneath Our Feet

　　第80课 我们脚下的土地

　　Perhaps you have seen men digging in the earth, either preparing for the foundations of a house, or making a deep ditch or a railway cutting. If you watch them at work, you will see that the earth which they turn up is not all of the same colour.

　　也许你看到过这样的场景：人们为了准备房屋的地基, 或者建造一条深沟或者铁路而挖土。观察他们的工作, 就会发现, 他们挖出来的泥土颜色不尽相同。

　　On the top there may be grass growing, and when the men cut through the tough network of its roots, they find a loose black or dark-brown earth which is easy to dig. This is called the soil.

　　土地的最上层可能长有一些花草, 当人们的挖掘工具穿过这些花草强韧的根部之后, 一层松软的黑色或深棕色泥土便露了出来。这就是土壤, 它们非常容易挖掘。

　　When they go a foot or two further down, they reach a kind of earth which is much lighter¹ in colour and much harder to dig. This is called the subsoil. If they have to dig still deeper, they will come after a while to the hard and solid rock. In some places the workmen may have to dig down only a few feet before they reach the rock, but in other places both the soil and the subsoil may be many feet deep. The depth varies very much in different spots.

　　当人们继续向下挖掘一至两英尺之后就会触碰到一种颜色较浅但很难挖掘的泥土, 它的名字叫做底土。如果还需要继续深挖, 不久之后就能看到坚硬的固体石头。有时候, 工人们可能只需挖掘几英尺便能看到岩石层；不过另外一些时候, 岩石层上方的土壤与底土可能达到很多英尺之厚。在不同的地方深度相差很大。

　　At one time the soil was just like the subsoil, and before that it formed part of some hard and solid rock. How are the hard rocks broken up and changed into soil? Chiefly by means of water. Rain-water dissolves the rock called limestone², just as your warm tea dissolves the lumps of sugar which you put into it, though more slowly. The tops of limestone hills are often worn into the most curious shapes by the action of the rain-water.

　　曾几何时, 土壤与底土一样结实, 再往前追溯的话, 它还曾经是坚硬、结实的岩石。如此坚硬的石头为何会碎裂并且变成土壤呢? 主要原因就是水。雨水能够溶解石灰岩, 就像温热的茶水能够溶解糖块一样, 只是前者的速度要缓慢很多。在雨水的作用下, 石灰石山的顶部会变成各种奇异的形状。

1 lighter   

n.打火机，点火器；驳船；v.用驳船运送；light的比较级

参考例句：

• The portrait was touched up so as to make it lighter.这张画经过润色，色调明朗了一些。
• The lighter works off the car battery.引燃器利用汽车蓄电池打火。

2 limestone   

n.石灰石

参考例句：

• Limestone is often used in building construction.石灰岩常用于建筑。
• Cement is made from limestone.水泥是由石灰石制成的。