大学英语自学考试英语二下册unit2教案.doc

UNIT 2

Text A　Black Holes

I课文简介
　　本文主要介绍了黑洞的概念，黑洞是怎样产生的，以及有关黑洞的一些研究。
　　对于黑洞的研究才刚刚起步，因此黑洞对于我们来说还很神秘，需要我们的不断探索。
　　什么是黑洞？ What is a black hole ?
　　宇宙中有一些点，它们的体积趋向于零而密度变得无穷大。由于具有强大的吸引力，物体只要进入离这些点一定距离内，就会被这强大的吸引力吸收掉，连光线也不例外。因此，没有任何信号能从这个范围内传出，这个范围的边界被称为"视界"(event horizon) 。视界里面的情况人类无法看到，所以科学家称之为"黑洞"。
　　一颗燃烧尽了的恒星由于自身的重力而不断塌陷，最后就会形成黑洞。尽管关于黑洞的理论是正确的，但是科学家一直在寻找黑洞存在的证据。
　　课文分为三部分：
　　Paragraph 1 What is a black hole ?
　　Paragraph 2 - paragraph 4 The theory of black holes
　　Paragraph 5 Speculations about black holes are endless .
II New Words
　　词汇精讲：

　　1 escape v.逃跑，避免
　　A lion has escaped from its cage.
　　一头狮子从笼子里跑出来了
　　2 exert: vt.用尽；尽力；运用；行使；施加，产生（影响等）
　　用法：exert pressure on sb.给…施加压力
　　She exerted herself all year to earn good marks.她整年努力以期获得好分数。
　　He's been exerting a lot of pressure on me to change my mind.他一直在施加种种压力要我改变主意。
　　Black holes exert very strong gravity.黑洞产生很强的引力。
　　3 explode v.爆炸，突发　　explosion n.　　explosive a.
　　A bomb exploded at one of London's busiest railway station this morning.
　　今天上午一颗炸弹在伦敦最繁忙的火车站爆炸了。
　　4 collapse v.n.倒塌, 崩溃
　　例句 参考教材第34-35页的 word Study 2
　　5 shrink: (shrank, shrunk ) v.退缩；畏缩；n.收缩；缩小
　　用法： The gross national product shrank one percent last year.去年国民生产总值减少了1%。
　　Washing wool in hot water will shrink it .在热水中洗羊毛会使它缩水。
　　We will never shrink back before difficulties .我们在困难面前决不退缩。
shrink+副词/介词短语 ： That sweater shrank in the wash.  The girl shrank back in fear.
Shrink+名词： This detergent won’t shrink wool 这种洗洁剂不会使毛料收缩。
6 boundary n.分界线，边界
　　We crossed the state boundary at midnight.
　　我们在午夜穿过了州界。
7 constant adj.不断的，经常的；永恒的，始终如一 n..常数
　　He is in constant trouble with the police.他总是不断和警察惹麻烦。
　　There are no constants at all.根本没有不变的事物。
对比同义词：
　　continual 时断时续的 It continually shrinks by the force of its own gravity
　　continuous 连续不间断的 The brain needs a continuous supply of blood.
　　 大脑需要不断的供血。
　　constant强调不变，永恒
8 implication: n.牵连；涉及；卷入；含意；暗示
　　派生词：imply v.暗示，含意
　　用法：She seemed by implication to acknowledge that fact.她似乎含蓄地承认了那事实。
　　 The implication of your statement is that I was wrong.你这话的弦外之音是我错了。
9．basis 基础、根据（复数为bases）
His theory has a solid basis in facts. 他的理论有很多事实根据。
10 launch: v.发射，发动 n.发射
　　The launch of the third man-made satellite turned to be a great success.第三枚航天器的发射结果是巨大成功。
　　 In the 1980's our country launched a number of satellites.80年代我国发射了多颗卫星。
11 convincing : a.令人信服的；有说服力的；
　　派生词：convince v.使人信服，使… 相信
　　用法：She is very convincing .她很另人信服。
　　Convince sb.of sth.使某人确信某事； convince sb.that 从句
　　We failed to convince him of his mistakes.我们没能使他相信他是错误的。
　　Careful observation convinced them that it was so.仔细的观察使他们相信情况是这样的。
12 companion : n.同伴，同行，伴侣，同事
　　派生词：company n.同伴，陪伴 ； accompany v.陪同，陪伴
　　用法：He is a good companion on the journey.他是个好旅伴。
　　表示"同事"的词：associate, colleague, fellow official, fellowworker, co-worker
13. speculation 
1)speculation+about/on upon+名词： 深思、揣想、推测
He made speculations on the purpose of life. 他对人生的目的进行深思。
2)peculation +in+名词： 对。。。投机
Speculation in stocks is a dangerous way of making a fortune. 股票投机是一种危险的发财方式。
14．swallow 
1)swallow+up+名词 ：吞没、吞。。。。 He swallowed up the medicine with water.
2)Swallow+名词： （口语）轻信、忍受 She couldn’t swallow his insults.
15 operate : v.操作，运行，起作用；动手术
　　派生词：operation n.操作
　　用法：The machine isn't operating properly.机器运转不正常。
　　He operated on the eyes of the patient.他给病人的眼睛动了手术。
　　Has the medicine started to operate ? 药物开始见效了吗？
16．result 
1)result+from+名词 ：由。。。造成。。。结果、 由。。。引起 
The terrible accident resulted from his carelessness. 那桩可怕的事故是因他的疏忽大意引起的。
2)result+in+名词：导致、引起 
His attempt resulted in failure. 他的尝试终于失败了。
17．reduce 
1)reduce+名词：把。。。减少、下降、减弱
She reduced her weight by 5 kilograms.
2)Reduce+名词＋to+名词/动名词 ：使。。。变为/成为（可用于被动语态）
The bobs reduced the city to ruins炸弹使那座城市变为废墟 
She was reduced to tears at the sight. 她看到那情景就哭了起来。

词组：phrases
　　1.to research into 研究
　　She is researching into possible cures for AIDS.
　　她正在研究治疗艾滋病的方法。
　　2 speculation about : 关于… 的猜测
　　We heard all kinds of speculation about the cause of the President's death.我们听到关于总统死亡原因的种种猜测。
　　People have much speculation about the government's intentions.对政府的意图，人们作了许多猜测。
　　3 to swallow up : 吞没；并吞
　　His wife's clothes bill swallowed up his wages .老婆买的衣服耗尽了他的工资。
　　The fog swallowed up the whole city.雾笼罩全城。
　　She swallowed the medicine with the help of some water.她用水把药咽下了。
　　 His figure was swallowed up in the dark.他的身影消失在黑暗中。
　　4 to make use of ：利用= to take advantage of
　　 We should make good use of our leisure time.我们应该好好利用休闲时间。
　　 He was making full use of his opportunity.他正充分利用他的机会。
　　to reduce … to 简化，归纳，迫使
　　Months' bombing reduced the city to ruins.
　　几个月的轰炸使这个城市变成了废墟
　　5 to apply to 适用于
　　It does not apply to you.它不适用于你。

III课文详解
第一部分　Para.1
1. What is a black hole?
文章开头首先提出问题：What is a black hole? （什么是黑洞？）
2. Well, it's difficult to answer this question, since the terms we would normally use to describe a scientific phenomenon are inadequate here.
it是形式主语，真正的主语是不定式短语to answer this question；since引导了原因状语从句，terms后面的we would … a scientific phenomenon是定语从句，关系代词which / that被省略；不定式短语to describe …充当目的状语。　inadequate = not enough
3. Astronomers and scientists think that a black hole is a region of space (not a thing) into which matter has fallen and from which nothing can escape-not even light.天文科学家和科学家认为黑洞是一个空间地带（不是物体），物质掉进去就难逃罗网，甚至连光也跑不了。
   关系代词在从句中作介词宾语时，若介词随着关系代词提前，关系代词不能使用that,若介词不提前，则不受此限制。 例如：I didn’t know the matter that/which you referred to. 我不知道你说的那件事。into which matter has fallen and from which nothing can escape是两个并列的定语从句，同时修饰a region of space，第一个定语从句以into which引导，而第二个定语从句以from which引导，因为有fall into和escape from搭配。
4. So we can't see a black hole.
5. A black hole exerts a strong gravitational pull and yet it has no matter.
exert相当于produce，意思是"产生"。a strong gravitational pull 一个很强的引力 = gravity
　　yet = but 但是
　　6. It is only space-or so we think.
so we think.是倒装句，"我们认为如此" ( we think so )
or so we think中的so意思是"这样"，指前一句的内容，有时置于主谓语之后，有时置于主谓语之前，例如：I think so. 我想是这样。当so表示"也"、"如此…（以致于…）"的意思时，so若置于句首，句子须倒装。例如：
Mary can play the piano. So can I. 玛丽会弹钢琴，我也会。
So beautiful is the flower that everybody likes it. 这朵花如此地漂亮，大家都喜欢它。
7. How can this happen?
此句中can是情态动词，表示可能性；通常，表示可能性的can用于否定句和疑问句。
第二部分
　　Para .2
1. The theory is that some stars explode when their density increases to a particular point; they collapse and sometimes a supernova occurs.
occur意思是"出现"。此句是复合句：that some stars explode when their density increases to a particular point 是表语从句； when their density increases to a particular point 是时间状语。
　　注意to a particular point 是固定搭配表示"达到某一点"
　　此句讲了超新星supernova产生的步骤，注意有四个不及物动词vi.的用法
　　explode increase collapse occur
2. From earth, a supernova looks like a very bright light in the sky which shines even in the daytime. 从地球上看，超新星就像是天空中一盏明亮的灯，即使在白昼中也闪闪发光
which引导的是定语从句，修饰前面的light，而不是sky。
in the daytime 与at night 相反，表示“在白昼” Stars are invisible in the daytime.
3. Supernovae were reported by astronomers in the seventeenth and eighteenth centuries.
supernovae是supernova的复数形式，也可以是supernovas。
4. Some people think that the Star of Bethlehem could have been a supernova. 有人认为圣诞星可能是一颗超新星。
could have been也表示可能性，表示的时间是过去，因为"can或could + have + 过去分词"指对过去的推测。I could have told you about it, but I don't remember it now.我可能给你说过这件事，但我现在记不得了。
5. The collapse of a star may produce a White Dwarf or a neutron star-a star, whose matter is so dense that it continually shrinks by the force of its own gravity.
a star是同位语成分，后面whose引导非限制性定语从句。注意 so… that 的用法
6. But if the star is very large (much bigger than our sun) this process of shrinking may be so intense that a black hole results. 如果恒星非常大（比太阳还大的多），那么其收缩过程就极为剧烈，以至产生了黑洞。
much可修饰比较级，表示"比…得多"；so … that… 意思是"如此…以致于…" So…that在此引导一个结果状语从句，从句谓语动词用陈述语气，若引导目的状语从句，从句谓语动词则用虚拟语气（can/could/may/might+动词原形）。例如：The writer explained so carefully that the reader could understand better.；result是result from…的省略，意为"（由…）产生"。在这里是不及物动词，表示“作为结果发生”，经常与介词in和from搭配分别表示“导致”和“是由。。。引起的”。
7. Imagine the earth reduced to the size of a marble, but still having the same mass and a stronger gravitational pull, and you have some idea of the force of a black hole.
该句结构是"Imagine … gravitational pull, and you have …"，相当于"If you imagine … gravitational pull, you have …"；所以，当有"Do…, and + 主语 + 动词 …"结构时，可把它改写为："If you do …, 主语 + 动词 …"；have some idea of意思是"对…有所了解"。
而"reduced … to marble "和"having … pull"分别为过去分词和现在分词短语作定语，修饰the earth；mass 质量；have some idea 略知一二
8. Any matter near the black hole is sucked in.
suck in意思是"吸进"。
9. It is impossible to say what happens inside a black hole.
It是形式主语，真正的主语是to say what … hole，在不定式中含有宾语从句what …。
10. Scientists have called the boundary area around the hole the "event horizon."
动词call后面接复合宾语结构，the "event horizon" 宾语补足语成分。
11. We know nothing about events which happen once objects pass this boundary.
which happen是定语从句，修饰events；once意思是"一旦"，引导时间状语从句。
12. But in theory, matter must behave very differently inside the hole.
must在此句中意思是"一定"，表示推测。
　Para. 3
1. For example, if a man fell into a black hole, he would think that he reached the center of it very quickly.
本句是表示与现在事实相反的虚拟语气。主句谓语动词用would think , if引导的条件状语从句谓语动词用过去时fell 。该句结构是"if 主语 + did + …, 主语 + would do …"，这叫非真实条件句，是虚拟语气结构表示与将来事实可能相反；非真实条件句的结构有：

2. However an observer at the event horizon would think that the man never reached the center at all.
该句中would think仍然是虚拟语气，语法上称这种句型为隐含条件句；never … at all或not … at all意思是"根本不"。
3. Our space and time laws don't seem to apply to objects in the area of a black hole. 我们的时空法则似乎不适用于黑洞区内的物体。（介词短语作定语）
seem后面可接that从句，形容词短语或to do sth；apply to意为"适用于、适应于"， 另有：apply for（申请），apply sth to sth（把…应用于…）。
4. Einstein's relativity theory is the only one which can explain such phenomena.
phenomena（现象）是phenomenon的复数形式。
5. Einstein claimed that matter and energy are interchangeable, so that there is no "absolute" time and space.
此句中so that引导结果状语从句，意为"因此、所以"，该短语有时表示"为了、以便"，有时表示"因此、所以"。试比较：

6. There are no constants at all, and measurements of time and space depend on the position of the observer.
no … at all意思是"根本没有"；depend on意为"依靠、依赖、取决于"。另有rely on, live on, feed on, rest on, draw on等搭配。
7. They are relative. relative反义词是absolute。
8. We do not yet fully understand the implications of the relativity theory; but it is interesting that Einstein's theory provided a basis for the idea of black holes before astronomers started to find some evidence for their existence.
not yet意思是"还没有"；it是形式主语，真正主语是that从句；provide sth for sb表示"为某人提供某物"，该结构也可作provide sb with sth；类似于provide的动词还有：furnish, present, supply。before引导时间状语从句
9. It is only recently that astronomers have begun specific research into black holes. 只是最近天文学家才真正开始研究黑洞。
It is … that …是强调结构，强调成分是时间状语only recently；该句使用了现在完成时，因为时间状语是recently；强调结构为 It is + 被强调部分 + that …；词research后面与介词into搭配，表示"对…的研究"。与for搭配表示“寻找。。。” 例
   如：Scientists carry out a research into the causes of cancer.
  Their search for the lost child ended in failure.
10. In August 1977, a satellite was launched to gather data about the 10 million black holes which are thought to be in the Milky Way.
to gather data …是不定式短语，充当目的状语；about引导的介词短语作定语修饰data ；data 的单数为datum；which 引导定语从句修饰 holes ； be thought to + 动词原形"意思是"据认为…"。
11. And astronomers are planning a new observatory to study the individual exploding stars believed to be black holes.
to study …是不定式短语，充当目的状语；.exploding 和believed to be black holes 均为分词作定语，修饰stars， believed…是过去分词短语，充当定语，可改为定语从句which are believed to …，"be believed to + 动词原形"意思是"据信…"。
　Para.4
1. The most convincing evidence of black holes comes from research into binary star systems.
evidence（证据）是不可数名词；名词research后面跟介词into搭配。
2. Binary stars, as their name suggests, are two stars whose position in space affects each other. 顾名思义，双星就是一对恒星，其空间位置相互影响。
Binary stars "双星系"；As在这里是一个关系代词，as their/its name suggests/ implies表示“顾名思义”。as their name suggests是非限制性定语从句，意思是"正如它们的名字所暗示的那样、顾名思义"，as可作关系代词，指代整个主句，引导非限制性定语从句，且该从句的位置灵活，可置于主句前面，或主句后面，或主句中间。例如： As you know, he is very clever. He is very clever, as you know. He is, as you know, very clever.
能够指代整个主句，且引导非限制性定语从句的关系代词只有两个：which 和as，但which引导的非限制性定语从句只能置于主句之后。which译为"这"，而as译为"正如"。例如：He said nothing, which made his girl friend angry.
3. In some binary systems, astronomers have shown that there is an invisible companion star, a "partner" to the one which we can see in the sky. 在一些双星系中，天文学家证明有一种看不见的伴星，即我们能够在天空中看到的那颗星的“伙伴”
a "partner" 是an invisible companion 的同位语；the one指代the star。
4. Matter from the one which we can see is being pulled towards the companion star.
此句中的the one同上句；pull意为"吸引"。
5. Could this invisible star, which exerts such a great force, be a black hole?
which exerts … force是this invisible star的非限制性定语从句，补充说明它；which用作定语从句的引导词，可用于限制性定语从句，也可用于引导非限制性定语从句。that 则不可用于引导非限制性定语从句。could be是该句的谓语动词部分，"could / can + 动词原形"可表示可能性，是对现在状态的推测，译为"可能、也许"；另有：

6. Astronomers have evidence of a few other stars too. Which might have black holes as companions.
该句中的might也可表示可能性，可用may替换，通常用于肯定句。它的结构有：

第三部分
　　Para.5
1. The story of black holes is just beginning.
此句的story应理解为"研究"。
2. Speculations about them are endless.
speculations about …意思是：关于…的假说。
3. There might be a massive black hole at the center of our galaxy swallowing up stars at a very rapid rate.
该句的might也表示可能性；swallow up意思是"吞没"，swallowing up …是现在分词短语，修饰前面的a massive black hole，可改为定语从句which / that is swallowing up …；名词rate或speed前面的介词用at。at the center of our galaxy 是状语；story 比较真实的故事fiction 不太真实的故事同义词：novel
4. Mankind may one day meet this fate.
5. On the other hand, scientists have suggested that very advanced technology could one day make use of the energy of black holes for mankind. 而科学家们认为，有朝一日高度发达的技术或许能利用黑洞的能量造福人类。
on the other hand意思是"另一方面"，试比较on (the) one hand（一方面）；此句中的suggest意思是"提出、认为"， 若表示"建议"，其宾语从句则必须使用虚拟语气，动词为：(should) do型；make use of意思是"利用"。 one day既可指（过去）有一天，也可以指（将来）总会有一天。 例如：one day we’ll get ourselves a new car.  
 6. These speculations sound like science fiction.
sound like意思是"听起来象"；比较：look like（看起来象）
7. But the theory of black holes in space is accepted by many serious scientists and astronomers.
本句是被动语态。
8. They show us a world which operates in a totally different way from our own and they question our most basic experience of space and time. 他们向我们展示了一个与我们这个世界运行方式完全不同的世界，并对我们最基本的时空体验提出了质疑。
show可后接双宾结构，此句us是直接宾语，a world是间接宾语；此句中which 引导限定性定语从句修饰world；in … way表示"以…的方法、方式"；different from是固定搭配。另有：the same as, similar to，Totally 是副词修饰different, 相当于completely. Question作及物动词用，表示“向某人提问，质问” She openly questioned the truth of this statement. 她公开对这件事的真实性表示怀疑。
重点句：
　　1.Well, it's difficult to answer this question, since the terms we would normally use to describe a scientific phenomenon are inadequate here. （第一段）
　　2.Astronomers and scientists think that a black hole is a region of space (not a thing ) into which matter has fallen and from which nothing can escape - not even light. So we can't