高中英语人教版高二下课文03

[00:02.35]地球

[00:04.70]READING  THE PROPERTIES OF WATER

[00:07.29]阅读  水的特性

[00:09.87]Earth is an ocean planet.

[00:11.76]地球是个水球。

[00:13.64]About three billion years ago,life on our planet began in the deep blue seas.

[00:17.32]大约有三十亿年以前，在我们的星球上，生命从蓝色的海洋深处开始。

[00:21.00]Ninety-nine percent of the living space on earth is in the oceans.

[00:24.28]地球上99%的生存空间是在海洋中，

[00:27.56]Marine 1 life is incredibly rich and varied 2.

[00:30.38]海洋生物非常丰富。

[00:33.20]There are about five million species 3 in the oceans

[00:35.88]海洋中大约有五百万种生物，

[00:38.56]and we have yet to learn much about them.

[00:40.69]还有很多有待我们去研究。

[00:42.81]Life in the oceans ranges from the tiniest plankton 4

[00:45.30]海洋中的生物种类包括最小的浮游生物

[00:47.78]all the way up to giants like sharks and whales.

[00:50.51]和像鲨鱼和鲸等最大的动物。

[00:53.24]What makes the ocean such a great place to live?The answer is water.

[00:56.57]是什么使海洋成为一个如此大的居住地呢？答案就是水。

[00:59.90]CHEMICAL STRUCTURE

[01:01.37]水的化学结构

[01:02.85]The chemical structure of water makes it an excellent medium for life.

[01:05.93]水的化学结构使它成为极好的生命介质。

[01:09.02]Water is actually quite simple,but the way the water molecule 5 if formed

[01:12.29]水实际上很简单，但水分子的构成方式赋予了它的独特的性质。

[01:15.57]gives water its unique properties.

[01:19.73]The water molecule is made up of two hydrogen atoms and one oxygen atom.

[01:23.36]水分子是由两个氢原子和一个氧原子组成。

[01:26.99]They form a polar molecule,that is,

[01:29.56]两个氢原子形一个有阴阳极的微粒子，

[01:32.13]one with a slightly positive end and a slightly negative end.

[01:35.36]即一个氢原子稍微带有阳极，另一个带有阴极。

[01:38.59]Because water is polar,it can break down both solids and gases.

[01:42.27]因为水是有阴阴极的，它可以分解或溶解气体和固体。

[01:45.95]The nutrients 6 in whatever falls into the ocean

[01:48.37]无论什么物质中的营养成分落入海洋中，

[01:50.79]quickly become available to other living creatures.

[01:53.31]就会让其了生物得到。

[01:55.83]The chemical structure of water

[01:59.77]also makes it different from almost everything else on earth.

[02:02.96]水的化学结构使得它几乎与世界所有其它物质不同。

[02:06.15]Water is a liquid at room temperature and has a relatively 7 high freezing point.

[02:10.12]水在室温下成液体状态，它且具有相对高的冰点。

[02:14.09]SALINITY 8

[02:15.52]盐度

[02:16.96]When dissolved gases and solids mix with pure water,

[02:19.89]当净水和可溶解的气体与固体混合时，

[02:22.81]the result is sea water,or salt water.

[02:25.79]结果就是海水或盐水。

[02:28.77]The salinity of the earth's oceans is about thirty-five per thousand,

[02:32.05]海洋的含盐量是35%。

[02:35.32]meaning that there are about thirty-five grammes

[02:37.81]即在1千克水中含有35克被溶解的气体和固体。

[02:40.29]of dissolved solids and gases in one kilogramme of water.

[02:43.62]尽管净水赋予了水的主要特性，

[02:46.95]Even though the pure water is what gives sea water its main properties,

[02:50.19]但是海水的盐度影响它的重要及冰点。

[02:53.43]the salinity of sea water affects both its weight and freezing point.

[02:56.76]但是海水的盐度影响它的重要及冰点。

[03:00.09]Salt water has a lower freezing point and is heavier than pure water.

[03:03.51]盐水比净水具有更低的冰点，比净水更重。

[03:06.93]DENSITY 9

[03:08.46]密度

[03:09.99]Density is the relationship between mass and volume

[03:12.88]密度是质量与体积之间的关系，

[03:15.76]and is measured in kilogrammes per cubie metre.

[03:18.24]密度用千克每立方米做单位（千克每立方米）

[03:20.72]The density of pure water is 1,000 kg/m3,

[03:24.06]水的密度是1000千克/米3。

[03:27.39]meaning that one cubic metre of water weighs one thousand kilogrammes.

[03:31.02]即一立方米水重一千千克。

[03:34.65]If a substance has a higher density,say 5,000 kg/m3,it will not float on water.

[03:39.57]如果某种物质有更高的密度，如5,000知克/立方米，它就不会浮在水面上。

[03:44.50]Marine animals and plants take a advantage of the density of water

[03:47.76]海洋生物利用水密度。

[03:51.03]With the right kind of body,it is possible to float around in the ocean

[03:54.31]有合适的体形，在海洋中就能四处漂浮，

[03:57.58]and let the water do the work.

[03:59.62]让海水发挥作用。

[04:01.66]When water freezes,its density decreases.

[04:04.30]当水结冰时，它密度会减少。

[04:06.94]If it did not,the oceans would be frozen 10 solid.

[04:09.76]若不是这样，整个海洋就会冻结成固体。

[04:12.58]HEAT CAPACITY

[04:14.05]热容

[04:15.53]Heat capacity is the amount of energy it takes to raise the temperature of a substance

[04:19.25]热容指的是一种物质的温度升高一摄氏度所需要的能量。

[04:22.97]by one degree centigrade.

[04:26.81]The heat capacity of water is relatively high.

[04:29.44]水的热容相对很高。

[04:32.07]Water can absorb and give off a lot of heat without big changes in temperature,

[04:35.89]温度改变不大，

[04:39.72]thus creating a stable environment.

[04:41.94]这样形成了稳定的环境。

[04:44.16]Most animals and plants are sensitive to large or sudden changes in temperature,

[04:47.70]大多数动物和植物对于巨大的或突然的温度变化很敏感，

[04:51.24]so the ocean is a safe and comfortable habitat.

[04:53.72]因而海洋是一既安全又舒适的栖息地。

[04:56.20]The water in the oceans also keeps the temperature of the earth steady

[04:59.32]海洋中的水也通过吸收或释放热量使地球的温度保持稳定。

[05:02.45]by absorbing and giving off heat.

[05:06.89]OCEAN MOTION

[05:08.41]海洋运动

[05:09.94]Since changes in slainity and temperature affect water's density,

[05:13.42]由于盐度和气温变化影响水的密度，

[05:16.89]the water in the ocean is always moving.

[05:19.37]海洋中的水一直在运动。

[05:21.85]Dense 11 water sinks and less dense water is pushed to the surface.

[05:25.28]密度大的水下沉，密度较小的水被推到海面。

[05:28.70]This circulation 12 adds energy to the marine ecosystems 13 and moves nutrients around.

[05:32.93]这种循环为海洋生态系统增加了能量并使营养成分四处游动。

[05:37.16]Isn't it amazing that a single substance can be so important to our planet

[05:44.53]and even the whole universe?

[05:48.00]Water,which seems so simple and common,is what makes life possible.

[05:55.37]Of all the resources on earth-oil,gas,gold and so on

[06:04.12]-nothing is as precious as a drop of rain.

[06:09.08]Learning about the properties of water helps us understand life on our planet.

[06:16.45]The most important thing we can learn about water,however,

[06:21.91]is that we must protect it and use it wisely.

[06:27.06]Our future depends on it.

[06:30.92]INTEGRATING SKILLS

[06:34.15]综合技巧

[06:37.37]Reading  NATURE'S NURSERY:ESTUARIES 14

[06:40.05]阅读    自然的保育院：入海口

[06:42.73]As the oceans are the source of life ib earth,

[06:47.30]the estuaries are our planet's nurseries.

[06:52.06]An estuary 15 is the body of water where a river meets the ocean.

[06:54.88]入海口就是一条河与海洋交汇的有很多水的地方。

[06:57.70]Salt water from the ocean and fresh water from the river

[07:00.43]从海中来的盐水和河流中来的淡水在入海口混合在一起。

[07:03.16]mix together in an estuary.

[07:07.23]This mixing of fresh and salt water

[07:09.41]这种盐水和淡水的混合

[07:11.60]creates a unique environment filled with life of all kinds-

[07:14.38]形成了一具独一无二的、充满各种生物的环境-

[07:17.16]a zone between the land and the sea.

[07:19.38]位于陆地与海洋之间的一个过渡的区域。

[07:21.60]Estuaries are the homes of thousands of animals and plants.

[07:24.40]入海口是成千上万种动植物的栖息地。

[07:27.19]Many cities and towns are built near estuaries,

[07:29.62]很多城市和城镇入海口建起，

[07:32.05]and a lot of fish is caught in estuaries.

[07:34.37]大量的鱼在入海口被捕捞。

[07:36.70]Estuaries are great places for nature's young ones.

[07:39.34]入海口对于自然中的细小生命来说是非常重要的地方。

[07:41.98]Here,animals can enjoy all the many of the benefits of teh oceans

[07:44.91]在这里，动物可以避开很多危险

[07:47.85]without having to fact many of the dangers.

[07:50.03]从而尽情享受海洋给其带来的益处。

[07:52.22]Tides provide energy for the ecosystems,

[07:54.54]潮汐为生态系统提供了能量，

[07:56.87]but estuaries are protected from waves and storms by islands,mud or sand

[08:00.73]但入海口受到保护使其免于受到波浪及岛屿、泥沙的袭击。

[08:04.60]Nutrients arrive in estuaries from both the land and the ocean.

[08:07.58]从陆地和海洋来的营养成分到达入海口。

[08:10.55]The density of living creatures is higher than in any other habitat on earth.

[08:13.83]生物的密度比地球上其他栖息地要高。

[08:17.11]The diversity of life in estuaries is incredible-birds,fish,marine mammals,

[08:21.04]入海口生物的多样性是惊人的-鸟、鱼、海洋哺乳动物、

[08:24.97]shellfish and other species all come here to live,feed and reproduce 16.

[08:28.85]贝类以及其它物种都来这和生活、捕食及繁殖。

[08:32.73]Estuaries are also important because they absorb nutrients

[08:35.60]入海口还非常重要是因为他们吸引从内陆来的水中的营养成分

[08:38.48]and pollutants 17 from water coming from inland sources,

[08:41.14]与污染物，

[08:43.81]thus cleaning our water.Unfortunately,

[08:46.18]这样就净化了水，不幸的是，

[08:48.56]this function also makes estuaries very sensitive to environmental pollution.

[08:51.94]这种功能也使入海口对于环境污染特别敏感。

[08:55.33]Since estuaries protect animals and plants from storms and floods

[08:58.46]既然入海口保护动植物不受风暴及洪水侵袭，

[09:01.60]and prevent erosion,protecting estuaries is very important.

[09:04.57]防止侵蚀，对其保护就非常重要。

[09:07.55]Finally,estuaries provide both recreation and education for human beings.

[09:11.24]最后，入海口既为人类提供了娱乐活动又提供了救育资源。

[09:14.92]Most of us enjoy fishing,swimming and having fun on the beach,

[09:17.95]我们大都喜欢在海滨钓鱼、游泳和游玩。

[09:20.98]and scientists and students have endless opportunities

[09:23.55]科学家们和学生有无数的机会研究

[09:26.13]to study a variety of life in the habitat.

[09:28.61]在这个地方的多种生物。

[09:31.09]Estuaries also contribute to the economy through tourism and fishing.

[09:34.32]入海口可通过旅游业和渔业促过经济的发展。

[09:37.54]INTEGRATING SKILLS

[09:50.81]Reading   LIFE IN THE OCEAN

[09:55.28]The earth's oceans can reach depths of up to 11,000 metres.

[10:01.94]That is deep enough to cover Mt Qomolangma!

[10:06.67]The oceans are incredibly large and contain several different habitats.

[10:13.51]To make it easier to describe the various parts of the oceans,

[10:19.26]marine scientists usually divide the oceans into five zones.

[10:26.23]Each zone is different mainly as a result of how much sunlight reaches it.

[10:32.89]Most of the life in the ocean can be found in the first zone,

[10:38.96]which begins at the surface and goes down about 200 metres.

[10:45.51]Because there is sunlight at this level,plants are able to grow.

[10:51.57]Marine animals such as dolphins,sharks,sea turtles and sea lions,

[10:59.12]and of course a variety of fish,

[11:03.09]live in the sunlit part such as dolphins,

[11:07.45]It is difficult to hide from other animals in this area,

[11:12.73]but many species have adapted by becoming dark on the top

[11:18.58]and light on the bottom.

[11:21.95]This makes it diffucult to see them against the dark water below

[11:27.91]and the blue sky above.

[11:32.17]The second zone starts at 200 metres and goes down to about 1,000 metres.

[11:39.72]Some sunlight can reach this level,but it is not enough for plants to grow.

[11:47.08]Because this zone is relatively dark,

[11:51.73]may of the creatures that live here are able to make light with their body.

[11:59.10]The light from these animals makes the water look like a sky

[12:04.66]with moving stars in it.

[12:08.42]The third zone of the ocean is dark.

[12:12.87]This place,about 3,000 metres deep,may not seem a likely habitat,

[12:20.31]but there are more creatures here than one might think.

[12:25.67]Most of the animals that live here are black or red because of the lack of light.

[12:33.42]At this depth,a slow shower of what looks like snow is falling.

[12:40.40]This phenomenon,called"marine snow",

[12:45.65]is actually nutrients falling towards the bottom of the ocean.

[12:51.71]It is important source of food for the creatures that live in the deep.

[12:57.59]Below 4,000 metres,

[13:01.24]the temperature is near freezing and there is no light at all

[13:07.12]In fact,the zone is so dark and empty

[13:12.76]that scientists named this zone after the Greek word for"no bottom".

[13:19.01]There is not much life to be found

[13:23.24]in this cold and unpleasant part of the ocean,

[13:27.78]but some small creatures still manage to survive here

[13:33.35]despite the high water pressure.

[13:37.19]Few of the animals inthe ocean can dive this deep.

[13:42.23]One exception is the sperm 18 whale,

[13:46.78]which slows its heartbeat in order to reach this zone as it hunts for food.

[13:53.85]The very deepest part of the ocean if found 2,000 metres further down.

[14:00.93]At this depth,the water pressure is extremely high

[14:06.68]and life is very difficult for the few creatures that live here.

[14:12.45]Compared to the other zones,this one has very little life.

[14:18.62]Since there is no light here,

[14:22.38]some of the animals do not have eyes.

[14:27.84]When scientists explored the very deepest parts of the ocean,

[14:33.40]they did not expect to find any life at all.

[14:38.58]However,it turned out that there are creatures

[14:43.54]that can live even in habitats as far down as 10,000 metres.

[14:51.12]They usually survive by living close to deep sea vents 19,

[14:57.46]"chimneys"that send out gases from within the earth.

[15:03.11]Unlike all other living things on the earth,

[15:07.76]which get their energy from the sun,

[15:11.73]the creatures that live here use chemicals from the vents to stay alive.

[15:18.99]Next time you look at the ocean from the beach or on a map,

[15:24.13]remember that what you are seeing is only the surface

[15:29.59]-Only the beginning of the large and caried adventure that is ocean