Soil Formation托福听力原文翻译及问题答案

Soil Formation托福听力原文翻译及问题答案

一、Soil Formation托福听力原文：

NARRATOR:Listen to part of a lecture in the geology class.MALE PROFESSOR:So,we all know soil.It's important to plant growth,right?And we know that there're different types of soil in different places and that some soils are more fertile than others.But what is soil?And how's it formed?Well,we're going to go into this in some depth,but for now let's just lay down the basics.

Soil is composed of two kinds of material:inorganic material,basically small pieces of rock,and organic material,which is animal and plant matter.

OK.So,what do you think?If I mix bits of rock with composted vegetables,will I get soil?The answer is no,because the formation of soil is a dynamic process.It involves not only the initial inputs,the raw materials,but also the transformation of those materials,and the movement of some of the materials and the loss of others.So,the inputs are bits of rock and organic matter.

Now,the bits of rock—the inorganic input to soil?uh...they come from the breakdown of rocks on Earth's surface through a process called weathering.Weathering can be either physical or chemical.Physical weathering,uh...that's when exposure to the elements over time causes a rock to break up and eventually disintegrate.Uh...of course,some rocks are more resistant to physical weathering than others.If you think of the sand particles in soil,those are the result of physical weathering,and they have the same chemical composition as the original rock.

Now,chemical weathering,uh...that's the chemical breakup of rocks.It differs from physical weathering in that the chemical properties of the minerals are actually changed.The clay minerals you find in soil are the result of chemical weathering.Clay minerals are called secondary minerals,because their composition has been altered.Okay.So we have weathered rock,which needs to be combined with organic matter.

So what does the organic input consist of?

It's the remains of plants and animals,but mostly plants.Now,just as rocks are broken down by weathering,the animal and plant residues are broken down,too.They're reduced to simple chemicals by microorganisms in a process called mineralization.And just as some rocks are more resistant than others to weathering,the compounds found in the soil's organic input resist mineralization at different rates.The compound cellulose is the major constituent of most plant tissue.It mineralizes relatively quickly.But there are woody substances in certain plants that strengthen the cell walls.They are found in smaller concentrations and their mineralization can take several years.Weathering and mineralization transform the inorganic and organic inputs in a number of ways.And it's partly from these transformations that soil gets its unique properties.

How does it work?

Uh...take the dark brown color of soil.After microorganisms have broken down the cellulose,we're left with two things:the microbe's waste and the more resistant plant material that microorganisms can't break down easily.These materials ultimately get transformed into a new material called humus.And when humus is combined with the clay minerals in soil,that's what gives soil its dark brown color.So now,if we've got clay and humus,these transformed materials,and we mix them together,we've got something very close to soil.

But soil isn't static,and there're still other processes that go into the formation of soil:the movement and loss of materials.The soil in any location isn't a uniform mixture.Its composition varies with depth.You see,mineral and organic materials move through soil vertically.Some materials move more easily than others.Water carries the more mobile materials from the upper level of soil to the lower levels.So the upper levels of the soil eventually get depleted of these materials,while the lower levels get enriched with them.And that creates distinct layers of soil as far down as the rock underlying the soil.And the materials that dissolve easily in water can get lost completely if the water carries them horizontally out of the soil and into rivers.

Now,of course,new mineral and organic material will be deposited at the surface and become incorporated into the soil,but you see how the processes of movement and loss contribute to the formation of soil.

二、Soil Formation托福听力中文翻译：

旁白：听地质学课上的部分讲座。男教授：所以，我们都知道土壤。这对植物的生长很重要，对吗？我们知道在不同的地方有不同类型的土壤，有些土壤比其他土壤更肥沃。但什么是土壤？它是如何形成的？好吧，我们将深入探讨这一点，但现在我们只需奠定基础。

土壤由两种物质组成：无机物质（基本上是小块岩石）和有机物质（即动植物物质）。

好啊那么，你认为呢？如果我把一些石头和堆肥蔬菜混合，我会得到土壤吗？答案是否定的，因为土壤的形成是一个动态的过程。它不仅涉及初始投入、原材料，还涉及这些材料的转化，以及一些材料的移动和其他材料的损失。因此，输入的是一些岩石和有机物。

现在，这些岩石碎片是无机物输入土壤的吗？嗯它们来自于地球表面岩石的风化过程。风化可以是物理的也可以是化学的。物理风化，呃。。。也就是说，随着时间的推移，暴露在这些元素中会导致岩石破碎并最终崩解。嗯当然，有些岩石比其他岩石更耐物理风化。如果你想想土壤中的沙粒，它们是物理风化的结果，它们的化学成分与原始岩石相同。

现在，化学风化，呃。。。这是岩石的化学分解。它不同于物理风化，因为矿物的化学性质实际上发生了变化。你在土壤中发现的粘土矿物是化学风化的结果。粘土矿物被称为次生矿物，因为它们的成分已经改变。可以所以我们有风化岩石，它需要与有机物结合。

那么有机输入由什么组成呢？

这是动植物的遗骸，但大部分是植物。现在，正如岩石被风化分解一样，动植物残留物也被分解了。微生物在一个叫做矿化的过程中将它们还原为简单的化学物质。正如一些岩石比其他岩石更耐风化一样，土壤有机输入中发现的化合物以不同的速率抵抗矿化。复合纤维素是大多数植物组织的主要成分。它矿化相对较快。但在某些植物中有木质物质可以加强细胞壁。它们的浓度较小，矿化可能需要几年时间。风化和矿化以多种方式改变无机和有机输入。土壤之所以具有独特的特性，部分是因为这些变化。

它是如何工作的？

嗯以土壤的深棕色为例。微生物分解纤维素后，我们剩下两样东西：微生物的废物和微生物不能轻易分解的抗药性更强的植物材料。这些物质最终转化为一种叫做腐殖质的新材料。当腐殖质和土壤中的粘土矿物结合时，土壤就会呈现深棕色。所以现在，如果我们有粘土和腐殖质，这些转化的物质，我们把它们混合在一起，我们就得到了非常接近土壤的东西。

但土壤并不是静止的，土壤的形成还有其他过程：物质的运动和流失。任何地方的土壤都不是均匀的混合物。其成分随深度而变化。你看，矿物和有机物质垂直穿过土壤。某些材质比其他材质更容易移动。水将流动性更强的物质从土壤的上层输送到下层。因此，上层土壤最终会耗尽这些物质，而下层土壤则富含这些物质。这就形成了不同的土壤层，直到土壤下面的岩石。如果水将易溶于水的物质水平带出土壤并流入河流，这些物质就会完全消失。

现在，当然，新的矿物和有机物质会沉积在地表，并融入土壤中，但你可以看到运动和流失过程如何促进土壤的形成。

三、Soil Formation托福听力问题：

Q1:1.What is the lecture mainly about?

A.The differences between mineralization and weathering.

B.Processes that remove minerals from soil.

C.Factors affecting the fertility of soil.

D.Several processes involved in the creation of soil.

Q2:2.What differences does the professor point out between sand particles and clay minerals?[Click on 2 answers.]

A.They combine with organic matter in different ways.

B.They are formed by different types of weathering.

C.The rocks they come from have different levels of resistance to weathering.

D.Only sand particles have the same composition as the rock they come from.

Q3:3.What does the professor point out about the compounds found in organic matter?

A.They mineralize at different rates.

B.They may resist combining with minerals in the soil.

C.They occur in roughly equal amounts in plant tissue.

D.They contain chemicals that are also found in inorganic materials.

Q4:4.Why does the professor mention the dark brown color of soil?

A.To explain that soil gets its color mainly from inorganic inputs.

B.To indicate that humus is more easily transformed than the other components of soil.

C.To show how the transformation and combination of inputs create the characteristics of soil.

D.To discuss how the characteristics of humus are changed by weathering.

Q5:5.According to the professor,how does water affect the composition of soil?[Click on 2 answers.]

A.It prevents new soil material from being incorporated.

B.It separates the components of soil into layers.

C.It causes chemical changes in the soil's organic material.

D.It can cause the loss of some of the soil material.

Q6:6.Why does the professor say this:(PROFESSOR)OK,so what do you think?If I mix bits of rock with composted vegetables,will I get soil?

A.To draw attention to the complexity of soil formation.

B.To stress the importance of organic matter in soil formation.

C.To imply that soil contains other,more important components.

D.To indicate one way soil can be formed.

四、Soil Formation托福听力答案：

A1:正确答案：D

A2:正确答案：BD

A3:正确答案：A

A4:正确答案：C

A5:正确答案：BD

A6:正确答案：A

>> 雅思 托福 免费测试、量身规划、让英语学习不再困难<<