高中英语人教版高二下课文03

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[00:00.00]和谐英语学习网 Unit 13 The water planet
[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 life is incredibly rich and varied.
[00:30.38]海洋生物非常丰富。
[00:33.20]There are about five million species 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
[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 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 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 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
[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
[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.