必修三 Unit 4 Astronomy: the Science Of The Stars天文学：恒星的科学
I．Vocabulary
II．Reading HOW LIFE BEGAN ON THE EARTH 地球上的生命是怎样开始的
No one knows exactly how the earth began, as it happened so long ago. 由于地球的产生是那么的久远，所以没有人确切知道地球是怎样产生的。【注释：as it happened 碰巧 eg. They were all out, as it happened.真巧, 他们全出去了。】 However, according to a widely accepted theory, the universe began with a “Big Bang” that threw matter in all directions.然而，根据一个广泛接受的理论，宇宙开始于一次“创世大爆炸”，该爆炸将物质抛向各个方向。【注释：in all directions四面八方；各个方向 eg. The birds flew away in all directions when he fired a salute with a“bang”.当他“砰”的一声鸣礼炮时，鸟飞向各个方向。】 After that, atoms began to form and combine to create stars and other bodies.之后，原子开始形成，并结合形成恒星和其他物体。
For several billion years after the “Big Bang”, the earth was still just a cloud of dust.就在“宇宙大爆炸”之后的几十亿年间，地球依然是一团尘埃。 What it was to become was uncertain until between 4.5 and 3.8 billion years ago when the dust settled into a solid globe.这一团尘埃会变成什么还不能确定，直到45亿至38亿年前，这团尘埃才形成一个固定的球体。【注释：settle into有头绪, 上正轨 eg. Things soon settled into shape.事情很快有了头绪。】 The earth became so violent that it was not clear whether the shape would last or not.地球变得如此剧烈，以致于它能否持续下来还不清楚。【注释：word/media/image1.gif so… that…如此…以致于…：eg. The words tumbled out so fast that I could barely hear them.话说得那么快，我几乎都听不清。
word/media/image2.gifit was not clear whether the shape would last or not.句中的it是形式主语，真正的主语是whether the shape would last or not.】 It exploded loudly with fire and rock. “大爆炸”发生时伴有(艳丽的)火焰和岩石。【注释：explode vt. & vi.使爆炸；爆发 explode with anger勃然大怒；explode with laughter哄然大笑；explode into laughter突然大笑起来；explode into pieces炸得粉碎。 如：Many people were injured when the boiler exploded.锅炉爆炸时，许多人受了伤。】 They were in time to produce carbon, nitrogen, water vapour and other gases, which were to make the earth’s atmosphere.他们最终形成了碳、氮、水蒸气和其它气体，而这些就构成了地球的大气。【注释：in time (1)迟早, 最后 eg. In time you'll forget him.你迟早会忘了他的。 (2)及时, 不迟 eg. He is believed to arrive in time.相信他会及时到达。 against time争分夺秒地，尽快地 eg. he was working against time.他正争分夺秒地工作。 ahead of time提前，提早 eg. We completed the work five days ahead of time.我们提前五天完成工作。 all the time一直，始终 eg. I have been busy all the time.我一直很忙。 at no time绝不，在任何情况下都不 eg. At no time will we give up.我们绝不屈服。 in no time立刻，马上 eg. I'll be back in no time.我马上就回来。 at one time曾经； at a time一次； at the same time同时，然而，可是；from time to time有时，偶尔
考题： 1. ______， I lost heart in English learning，but my teacher often said to me，“Keep on studying hard, and you’ll succeed _______.”
A．At a time；in time B．At a time；on time C．At one time；in time D．At one time；on time
2. —Does he often ask you for help? —Oh，no，only________.
A．all the time B．at one time C．at a time D．at times
3．—I am afraid I can’t return the book to you before Friday. —________.
A．Don’t be afraid B．Be careful C．Not at all D．Take your time 】
What is even more important is that as the earth cooled down, water began to appear on its surface.更为重要的是：当地球冷却下来后，水开始在地球表面出现了。【注释：word/media/image1.gif what is even more important是由what引导的名词从句作主语；that…on its surface是由that引导的名词从句作表语，系表语从句，在这个表语从句中又含有由as引导的时间状语从句。
word/media/image2.gifwhat is more 而且, 此外; 更有甚者 eg. They are going to get married, and what's more they are setting up in business together.他们就要结婚了, 而且还要一起做生意呢。】
Water had also appeared on other planets like Mars but unlike the earth, it had disappeared later.水在其它行星上如火星也出现过，不过，不像地球上，它消失了。 It was not immediately obvious that water was to be fundamental to the development of life.（但），这并没有立刻就表明：水是生命发展的必要部分。【注释：word/media/image1.gif fundamental adj.基本的; 重要的, 必要的 eg. Fresh air is fundamental to good health.新鲜空气对健康是不可缺少的。
word/media/image2.gifIt was not immediately obvious that…句中的“it”是形式主语，that从句是真正的主语从句。 】 What many scientists believe is that the continued presence of water allowed the earth to dissolve harmful gases and acids into the oceans and seas.许多科学家认为水的持续存在让地球将有害的气体和酸溶解到海洋中去。【注释：
word/media/image1.gifWhat many scientists believe是由what引导的主语从句，作整个句子的主语。
word/media/image2.gifdissolve vt. & vi.(使)溶解 eg. The sun dissolves snow.太阳使雪融化。
word/media/image3.gifharmful adj. 有害的；伤害的 be harmful to…对…有害处 eg. Smoking is harmful to your health.吸烟有害健康。 do sb. harm/ do harm to sb.对某人有害； do more harm than good弊大于利； There is no harm in (sb’s) doing sth.(= It does no harm (for sb.) to do sth.)做某事无害处； come to harm身体上、精神上或道义上受到损害；do sb. good/ do good to sb.对某人有好处。如： 1) The court case will do serious harm to my business.这起诉讼案件将严重损害我的生意。 2) My brother's ship was caught in a storm but he came to no harm.我兄弟的船遇上了暴风雨, 但他没出事。 3) You should do good to others.你应该对人行善。 4) If we interfere, it may do more harm than good.如果我们干预的话, 可能弊多利少。】 This produced a chain reaction, which made it possible for life to develop.这产生了一系列的反应，这种反应使得生命的产生成为可能。【注释：made it possible for life to develop中的 “it”是形式宾语，真正的宾语为for life to develop.】
Many millions of years later, the first extremely small plants began to appear on the surface of the water.数百万年之后，在水的表面上开始出现最初的极其微小的植物。【注释：extremely adv.极端;极其;非常 eg. 1) That is extremely interesting.那极为有趣。 2) Outwardly she looked confident but in reality she felt extremely nervous.表面上她显得很自信,其实她非常紧张。】 They multiplied and filled the oceans and seas with oxygen, which encouraged the later development of early shellfish and all sorts of fish.他们开始繁殖，并使得海洋充满了氧气，而这又激励了早期的贝壳类动物和所有鱼类的发展。【注释：word/media/image1.gif multiply (1)乘, (使)相乘 eg. 1) His son is learning to multiply and divide.他儿子正在学习乘法和除法。 2) One can make 18 by multiplying 3 and 6 (together).以3和6相乘可得18。 (2) (使)增加 eg. 1) Spending on military equipment has multiplied in the last five years.过去的五年中军事装备的开支大大增加。 2) His experience was multiplied as the years passed.随着岁月的流逝, 他的经验丰富了。(3) (使)繁殖 eg. 1) When animals have more food, they generally multiply faster.动物在有较多的食物时, 一般繁殖得较快。 2) Hot weather multiplied the bacteria in milk rapidly.炎热的天气使牛奶中的细菌迅速繁殖。
word/media/image2.giffill … with sth.用…装满 eg. I filled up the bottle with water.我把瓶子装满了水。 】 Next, green plants began to grow on land.随后，绿色植物开始在陆地上出现。 They were followed in time by land animals.最后，陆地动物跟着出现。 Some were insects.有些是昆虫。 Others, called amphibians, were able to live on land as well as in the water.其它的，被称为两栖类的，既能够生活中水中，也能生活在陆地。【注释：as well as conj.还，而且 eg. she is a talented musician as well as being a photographer. 她不但是个摄影师而且还是个天才的音乐家. 】 Later when the plants grew into forests, reptiles appeared for the first time.后来，当植物长成森林后，爬行类动物开始第一次出现。【注释：for the first time第一次，在句子作状语；the first time常用于引导(状语)从句：(1) It’s the first time sb. have done sth. (2) Sb. was doing sth. the first time I came here.】 They produced young generally by laying eggs.一般情况下，他们通过下蛋产幼仔。 After that , some huge animals, called dinosaurs, developed.而后，一些大型动物——恐龙，产生了。 They laid eggs too and existed on the earth for more than 140 million years.恐龙也下蛋，在地球上存在了1亿4千多万年。 However, 65 million years ago the age of the dinosaurs ended.可是，在6千5百万年前，恐龙世纪结束。 Why they suddenly disappeared still remains a mystery.恐龙为什么突然消失依然还是个迷。 【注释：sth. remain to be done某事有待于解决】This disappearance made it possible the rise of mammals on the earth.恐龙的消失使得哺乳动物在地球上的兴起成为可能。 These animals were different from all life forms in the past, because they gave birth to young baby animals and produced milk to feed them.这种动物不同于过去所有的生命形式，因为他们生产幼子，并且产奶来喂养幼子。【注释：give birth to…生; 引起, 产生 eg. 1) She gave birth to a fine healthy baby.她生了一个健康可爱的婴儿。 2） The scientist's experiments gave birth to a new drug.那位科学家的实验产生了一种新药。】
Finally about 2.6 million years ago some small clever animals, now with hands and feet, appeared and spread all over the earth.最后，大约在2百6十万年前，一些小的聪明的动物，现在有手有脚，出现，遍及到各个角落。【注释：spread all over遍及； spread sth. (out) on/ over sth.在…上展开/摊开； spread oneself（=stretch oneself）舒展四肢； spread out散开；伸展； spread to传到；波及，蔓延到； word spread消息传开。 辨析： extend, spread, stretch, expand (1) extend:伸出；延伸 指空间范围的扩大，以及长度、宽度的朝外延伸，也指时间的延长。如： 1) The headmaster extended(= prolong) our holiday by four days. 2) France has greatly extended its influence in world affairs.在世界事务中, 法国的影响已大大地扩大了。 (2) spread指向四面八方扩大宣传的范围，如传播疾病，散布信息的 (3) stretch伸展；拉长（=extend） 一般指由曲变直，由短变长的伸展。如：stretch/ extend the radio antenna.将天线拉长。 (4) expand扩大，不仅指尺寸的增加，还可指范围和体积的扩大。如：expand his store扩大店面。 Air expands when heated.空气受热膨胀。 试题： Papermaking began in China and from here it ____ to North Africa and Europe. A. spread B. grew C. carried D. developed 】
Thus they have, in their turn, become the most important animals on the planet.这样，轮到他们，成为这个星体上最重要的动物。【注释：in one’s turn轮到某人； it’s your turn。该你了！in turn 依次，轮流；反之，反过来；by turns轮流；交替地；take turns to do sth.轮流做某事；It is one’s turn to do sth.轮到某人做某事。考题：People try to avoid public transportation delays by using their own cars, and this _____ creates further problems. A．in short B．in case C．in doubt D．in turn 】
But they are not looking after the earth very well.但，他们却不能很好地呵护好地球。 They are putting too much carbon dioxide into the atmosphere, which prevents heat from escaping from the earth into space. 他们把太多的二氧化碳排放到大气中，这就阻碍了热从地球散发到太空。【注释：prevent/stop …(from)…阻止, 防止 eg. 1) My only idea was to prevent the woman from speaking.我唯一的想法就是不让那女人讲话。 2) Cotton mittens will prevent the baby from scratching his own face.棉的连指手套使婴儿不会抓伤自己的脸。 3) His prompt action prevented the fire from spreading.他的果断行动制止了火势的蔓延。考题：All possible means ________.However，nothing can________him dying of lung cancer.
A．has tried；stop B．have tried；keep C．has been tried；prevent D．have been tried; stop 】
As a result of this, many scientists believe the earth may become too hot to live on.由于这样，许多科学家认为地球将会变得炎热难住。【注释：live on (1) 住在…上 eg. I have always wanted to live on an island in the middle of a lake.我总是想在一座湖心小岛上生活。 (2) 继续活着; 继续存在 eg. 1) He's ninety, but still he lives on.他90岁了, 还健在。 2) These traditions will live on for centuries.这些传统将世代相传。】 So whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved.所以，生命能否在地球上继续存在数百万年将取决于这个问题能否得以解决。
试题：
1. She started as an office junior, and ____ became the director of the whole company.
A. in surprise B. in return C. in turn D. in time
2. He is always ready to help others and many people ____ a live Lei Feng.
A. to think of him as B. think of him as C. think him like D. look him as
3. _____ you are familiar with the author’s ideas, try reading all the sections as quickly as you possibly can.
A. Now that B. Ever since C. So that D. As long as
4. It is not expected ____ he said caused so much discussion at the meeting.
A. that B. what that C. what D. that what
5.* Animals suffered at the hands of man ____ they were destroyed by people to make way for agricultural land to provide food for more people.
A. in which B. for which C. so that D. in that
6. The young dancers looked so charming in their beautiful clothes that we took ___ pictures of them.
A. many of B. masses of C. the number of D. a large amount of
重点句型：
1．What it was to become was uncertain until between 4.5 and 3.8 billion years ago when the dust settled into a solid globe.【精提取】 What it was to become是what引导的主语从句，what在从句中作become的宾语。【巧应用】 使大家惊奇的是他竟没有参加会议。
________ ________ ________ ________ ________he didn’t come to the meeting.
答案：What surprised everybody is that
2．The earth became so violent that it was not clear whether the shape would last or not.
【精提取】 whether...(or not)引导的从句还可充当宾语、表语、同位语等。
【巧应用】 他是否能成功地通过驾驶考试还不确定。
It is uncertain_______ ______ ________ ________passing the driving test ____ ________.
答案：whether he'll succeed in; or not
3．This produced a chain reaction, which made it possible for life to develop.
【精提取】 which引导非限制性定语从句，指代主句整个概念，也可代指单个先行词。
【巧应用】 杰克开车太快，这是危险的。
Jack drove too fast，________ ________ ________. 答案：which was dangerous
4．We watched，amazed as fire broke out on the outside of the spaceship as the earth’s gravity increased.【精提取】 amazed是形容词化的过去分词，在此处作状语用。
【巧应用】 他躺在床上，醒着。
He ________ ________ ________ ________，________. 答案：lay on the bed，awake
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