首先，有几个基本概念我们要了解。第一，heading其实本质就是段落大意题，也就是我们在老外的文章中经常看到的topic sentence所包含的内容。第二，细节的作用是什么？细节是用来拓展主题句，帮助段落发展的利器。由此得出，段落大意在某种程度上可以帮助我们定位细节出处。同时，细节的内容比较清楚的同时可以帮助我们确认段落大意。两者相辅相成，到底哪个先行呢？

首先，通过剑桥9Test1 Passage2<Is Anybody Out There>的分析，我们来确认一下。

READING PASSAGE 2

You should spend about 20 minutes on Questions 14-26, which are based on ReadingPassage 2 on the following pages.

Questions 14-17

Reading Passage 2 has five paragraphs, A-E.

Choose the correct heading for paragraphs B-E from the list of headings below.

Write the correct number, i-vii, in boxes 14-17 on your answer sheet.

         14     Paragraph B

         15     Paragraph C

         16     Paragraph D

         17     Paragraph E

IS THERE ANYBODY OUT THERE?

The Search for Extra-terrestrial Intelligence

The question of whether we are alone in theUniverse has haunted humanity for centuries,but we may now stand poised on the brink ofthe answer to that question, as we search forradio signals from other intelligent civilisations.This search, often known by the acronym SETI(search for extra-terrestrial intelligence), is adifficult one. Although groups around the worldhave been searching intermittently for threedecades, it is only now that we have reachedthe level of technology where we can make adetermined attempt to search all nearby starsfor any sign of life.

A

The primary reason for the search is basic curiosity - the same curiosity about the naturalworld that drives all pure science. We want to know whether we are alone in the Universe.We want to know whether life evolves naturally if given the right conditions, or whether thereis something very special about the Earth to have fostered the variety of life forms thatwe see around us on the planet. The simple detection of a radio signal will be sufficient toanswer this most basic of all questions. In this sense, SETI is another cog in the machineryof pure science which is continually pushing out the horizon of our knowledge. However,there are other reasons for being interested in whether life exists elsewhere. For example,we have had civilisation on Earth for perhaps only a few thousand years, and the threats ofnuclear war and pollution over the last few decades have told us that our survival may betenuous. Will we last another two thousand years or will we wipe ourselves out? Since thelifetime of a planet like ours is several billion years, we can expect that, if other civilizationsdo survive in our galaxy, their ages will range from zero to several billion years. Thus anyother civilisation that we hear from is likely to be far older, on average, than ourselves. Themere existence of such a civilisation will tell us that long-term survival is possible, and givesus some cause for optimism. It is even possible that the older civilisation may pass on thebenefits of their experience in dealing with threats to survival such as nuclear war and globalpollution, and other threats that we haven't yet discovered.

B

In discussing whether we are alone, most SETI scientists adopt two ground rules. First.UFOs (Unidentified Flying Objects) are generally ignored since most scientists don'tconsider the evidence for them to be strong enough to bear serious consideration(although it is also important to keep an open mind in case any really convincing evidenceemerges in the future). Second, we make a very conservative assumption that we arelooking for a life form that is pretty well like us, since if it differs radically from us we maywell not recognise it as a life form, quite apart from whether we are able to communicatewith it. In other words, the life form we are looking for may well have two green headsand seven fingers, but it will nevertheless resemble us in that it should communicate withits fellows, be interested in the Universe, live on a planet orbiting a star like our Sun. andperhaps most restrictively, have a chemistry, like us, based on carbon and water.

C

Even when we make these assumptions, our understanding of other life forms is stillseverely limited. We do not even know, for example, how many stars have planets, and wecertainly do not know how likely it is that life will arise naturally, given the right conditions.However, when we look at the 100 billion stars in our galaxy (the Milky Way), and 100billion galaxies in the observable Universe, it seems inconceivable that at least one ofthese planets does not have a life form on it; in fact, the best educated guess we canmake, using the little that we do know about the conditions for carbon-based life, leads usto estimate that perhaps one in 100,000 stars might have a life-bearing planet orbitingit. That means that our nearest neighbours are perhaps 100 light years away, which isalmost next door in astronomical terms.

D

An alien civilisation could choose many different ways of sending information across thegalaxy, but many of these either require too much energy, or else are severely attenuatedwhile traversing the vast distances across the galaxy. It turns out that, for a given amountof transmitted power, radio waves in the frequency range 1000 to 3000 MHz travel thegreatest distance, and so all searches to date have concentrated on looking for radio wavesin this frequency range. So far there have been a number of searches by various groupsaround the world, including Australian searches using the radio telescope at Parkes, NewSouth Wales. Until now there have not been any detections from the few hundred starswhich have been searched. The scale of the searches has been increased dramatically since1992, when the US Congress voted NASA $10 million per year for ten years to conduct athorough search for extra-terrestrial life. Much of the money in this project is being spenton developing the special hardware needed to search many frequencies at once. The projecthas two parts. One part is a targeted search using the world's largest radio telescopes, theAmerican-operated telescope in Arecibo, Puerto Rico and the French telescope in Nancyin France. This part of the project is searching the nearest 1000 likely stars with highsensitivity for signals in the frequency range 1000 to 3000 MHz. The other part of theproject is an undirected search which is monitoring all of space with a lower sensitivity, usingthe smaller antennas of NASA's Deep Space Network.

E

There is considerable debate over how we should react if we detect a signal from an aliencivilisation. Everybody agrees that we should not reply immediately. Quite apart from theimpracticality of sending a reply over such large distances at short notice, it raises a hostof ethical questions that would have to be addressed by the global community before anyreply could be sent. Would the human race face the culture shock if faced with a superiorand much older civilisation? Luckily, there is no urgency about this. The stars beingsearched are hundreds of light years away, so it takes hundreds of years for their signal toreach us, and a further few hundred years for our reply to reach them. It's not important,then, if there's a delay of a few years, or decades, while the human race debates thequestion of whether to reply, and perhaps carefully drafts a reply.

Questions 18-20

Answer the questions below.

Choose NO MORE THAN THREE WORDS AND/OR A NUMBER from the passage foreach answer.

Write your answers in boxes 18-20 on your answer sheet.

18     What is the life expectancy of Earth?

19     What kind of signals from other intelligent civilisations are SETI scientists searchingfor?

20     How many stars are the world's most powerful radio telescopes searching?

Questions 21-26

Do the following statements agree with the views of the writer in Reading Passage 2?

In boxes 21-26 on your answer sheet, write

         YES                              if the statement agrees with the views of the writer

         NO                               if the statement contradicts the views of the writer

         NOT GIVEN                if it is impossible to say what the writer thinks about this

21     Alien civilisations may be able to help the human race to overcome serious          problems.

22     SETI scientists are trying to find a life form that resembles humans in many ways.

23     The Americans and Australians have co-operated on joint research projects.

24     So far SETI scientists have picked up radio signals from several stars.

25     The NASA project attracted criticism from some members of Congress.

26     If a signal from outer space is received, it will be important to respond promptly.

我们可以看到，这篇文章总共由三个题型组成，heading题加上两个细节题-简答和判断题。大部分学生都认为简答题和判断题属于两个相对简单的题型，同时比较惧怕heading题，再扫一下有几个相对比较明显的定位词，可能会选择先做细节题。让我们一起来看一下。

18题，定位词可以是life expectancy of Earth, 确认了定位词之后我们马上回到原文去定位寻找。搜查一圈之后无果。仍旧不放弃，选择看第19题，有SETI大写，是很明显的定位词，但是回到原文依旧无从下手，SETI在原文中反复出现，依旧一头雾水。

其实这篇文章相对来说比较简单的一个做题方式是先确认heading题的答案，再由段落大意来辅助定位细节。

A段已经给出例子，段落大意主要讲的是要探究外太空的理由，这时候我们可以发散思维，引导思考可能的理由，比如地球资源枯竭污染严重等，也可以看到首句要表达的主要原因是curiosity。

B段topic sentence是最后一句In other words, the life form we are looking may well have two green heads and seven fingers, but it will nevertheless resemble us in that it should communicate with its fellows.....所以确认heading题的答案是IV（当然C段的开头也可以帮助我们确认到这个答案，下文会说明）。然后我们会惊奇地发现，这个帮助heading做题的句子恰好可以判断22题的答案，而不需要用SETI这种满篇文章都有的词来帮助我们定位。

C段的topic sentence是该段落倒数第二段，...estimate that perhaps one in 100,000 stars might have a life-bearing planet orbiting it. 根据该句子，我们可以轻松判断这个段落主要是推测外太空存在生物的可能性的。

D段第二句话是明显的主题句，it turns out的结论就是我们需要精读的，从而可以判定这个段落主要是在探讨radio signal的搜寻。抓住D段主要内容之后，后面几道细节题包括第19题，第20题，第23和24题都分别会出自于这个段落，因为这几道题目当中的定位词都包括了radio signal这样的词。并且针对第20题，我们只需要确认答案是一个数字，精准快速找到答案就不是一个难点。

E段也就是原文的最后一段主要讲的内容就是找到信号之后该如何回应的问题，所以了解段落大意之后，26题也就迎刃而解了。

现在我们其实只剩下18题和21题没有找到明显的出处，但是有一个好处就是我们的答案其实显而易见。回到我们刚刚说到的文章结构分析，第一段的内容应该是探究外太空的原因，可以包括地球的寿命和有助于应对地球污染和资源短缺的问题。精读首段不难发现，18题当中的定位词life expectancy其实没有一模一样的对应，是被替换的了。对应的句子是Since the lifetime of a planet like ours is several billion years, we can expect that, if other civilization..., 非常简单，我们的答案就是several billion years。第20题的定位词我们会希望可以在原文中找到比较明显的alien civilizations, human race, serious problems, 判定的词组是may be able to overcome, 但是我们在首段定位不到的，因为“阴险”的考试官方又一次替换了我们的关键词，而是出现了如下的句子，"It is even possible that the older civilization may pass on the benefits of their experience in dealing with threats to survival such as nuclear war and global pollution, and other threats that we have not yet discovered. 然后我们就可以比较安全地确认该题的答案是TRUE。

针对这篇文章的分析，我们可以比较安全地得出结论，针对这篇文章“定位难，跨段远”的特点，先了解每段话的段落大意对细节题的定位和做题有着非常好的指向，缩短做题时间，提高准确率。

但是，遇到段落大意不清晰，文章内容不理解的问题，我们又应该怎么处理呢？是不是先针对细节题会帮助我们做题呢？下面，我们可以利用剑8 Test2 Passage2来分析一下。

READING PASSAGE 2

You should spend about 20 minutes on Questions 14-26, which are based on Reading Passage 2 on the following pages.

Questions 14-17

Reading Passage 2 has six paragraphs, A-F.

Choose the correct heading for paragraphs B and D-F from the list of headings below.

Write the correct number, i-ix, in boxes 14-17 on your answer sheet.

14     Paragraph B

15     Paragraph D

16     Paragraph E

17     Paragraph F

THE LITTLE ICE AGE

A

This book will provide a detailed examination of the Little Ice Age and other climatic shifts, but, before I embark on that, let me provide a historical context. We tend to think of climate - as opposed to weather - as something unchanging, yet humanity has been at the mercy of climate change for its entire existence, with at least eight glacial episodes in the past 730,000 years. Our ancestors adapted to the universal but irregular global warming since the end of the last great Ice Age, around 10,000 years ago, with dazzling opportunism. They developed strategies for surviving harsh drought cycles, decades of heavy rainfall or unaccustomed cold; adopted agriculture and stock-raising, which revolutionised human life; and founded the world's first pre-industrial civilisations in Egypt, Mesopotamia and the Americas. But the price of sudden climate change, in famine, disease and suffering, was often high.

B

The Little Ice Age lasted from roughly 1300 until the middle of the nineteenth century. Only two centuries ago, Europe experienced a cycle of bitterly cold winters; mountain glaciers in the Swiss Alps were the lowest in recorded memory, and pack ice surrounded Iceland for much of the year. The climatic events of the Little Ice Age did more than help shape the modern world. They are the deeply important context for the current unprecedented global warming. The Little Ice Age was far from a deep freeze, however; rather an irregular seesaw of rapid climatic shifts, few lasting more than a quarter-century, driven by complex and still little understood interactions between the atmosphere and the ocean. The seesaw brought cycles of intensely cold winters and easterly winds, then switched abruptly to years of heavy spring and early summer rains, mild winters, and frequent Atlantic storms, or to periods of droughts, light northeasterly winds, and summer heat waves.

C

Reconstructing the climate changes of the past is extremely difficult, because systematic weather observations began only a few centuries ago, in Europe and North America. Records from India and tropical Africa are even more recent. For the time before records began, we have only 'proxy records' reconstructed largely from tree rings and ice cores, supplemented by a few incomplete written accounts. We now have hundreds of tree-ring records from throughout the northern hemisphere, and many from south of the equator, too, amplified with a growing body of temperature data from ice cores drilled in Antarctica, Greenland, the Peruvian Andes, and other locations. We are close to a knowledge of annual summer and winter temperature variations over much of the northern hemisphere going back 600 years.

D

This book is a narrative history of climatic shifts during the past ten centuries, and some of the ways in which people in Europe adapted to them. Part One describes the Medieval Warm Period, roughly 900 to 1200. During these three centuries, Norse voyagers from Northern Europe explored northern seas, settled Greenland, and visited North America. It was not a time of uniform warmth, for then, as always since the Great Ice Age, there were constant shifts in rainfall and temperature. Mean European temperatures were about the same as today, perhaps slightly cooler.

E

It is known that the Little Ice Age cooling began in Greenland and the Arctic in about 1200. As the Arctic ice pack spread southward, Norse voyages to the west were rerouted into the open Atlantic, then ended altogether. Storminess increased in the North Atlantic and North Sea. Colder, much wetter weather descended on Europe between 1315 and 1319, when thousands perished in a continent-wide famine. By 1400, the weather had become decidedly more unpredictable and stormier, with sudden shifts and lower temperatures that culminated in the cold decades of the late sixteenth century. Fish were a vital commodity in growing towns and cities, where food supplies were a constant concern. Dried cod and herring were already the staples of the European fish trade, but changes in water temperatures forced fishing fleets to work further offshore. The Basques, Dutch, and English developed the first offshore fishing boats adapted to a colder and stormier Atlantic. A gradual agricultural revolution in northern Europe stemmed from concerns over food supplies at a time of rising populations. The revolution involved intensive commercial farming and the growing of animal fodder on land not previously used for crops. The increased productivity from farmland made some countries self-sufficient in grain and livestock and offered effective protection against famine.

F

Global temperatures began to rise slowly after 1850, with the beginning of the Modern Warm Period. There was a vast migration from Europe by land-hungry farmers and others, to which the famine caused by the Irish potato blight contributed, to North America, Australia, New Zealand, and southern Africa. Millions of hectares of forest and woodland fell before the newcomers' axes between 1850 and 1890, as intensive European farming methods expanded across the world. The unprecedented land clearance released vast quantities of carbon dioxide into the atmosphere, triggering for the first time humanly caused global warming. Temperatures climbed more rapidly in the twentieth century as the use of fossil fuels proliferated and greenhouse gas levels continued to soar. The rise has been even steeper since the early 1980s. The Little Ice Age has given way to a new climatic regime, marked by prolonged and steady warming. At the same time, extreme weather events like Category 5 hurricanes are becoming more frequent.

Questions 18-22

Complete the summary using the list of words, A-l, below.

Write the correct letter, A-l, in boxes 18-22 on your answer sheet.

Weather during the Little Ice Age

Documentation of past weather conditions is limited: our main sources of knowledge of conditions in the distant past are 18...................... and 19...................... . We can deduce that the Little Ice Age was a time of 20...................... , rather than of consistent freezing. Within it there were some periods of very cold winters, others of 21...................... and heavy rain, and yet others that saw 22...................... with no rain at all.

Questions 23-26

Classify the following events as occurring during the

         A      Medieval Warm Period

         B       Little Ice Age

         C       Modern Warm Period

Write the correct letter, A, B or C, in boxes 23-26 on your answer sheet.

23     Many Europeans started farming abroad.

24     The cutting down of trees began to affect the climate.

25     Europeans discovered other lands.

26     Changes took place in fishing patterns.

B段的topic sentence隐藏得比较深，在我们精读首句尾句之后发现内容分别是little ice age的主要时间段和天气的内容，对应不到heading的选项。那我们看了首尾句的时间是浪费了吗？答案是否定的。回到细节我们可以发现，summary题的标题就是weather during the little ice age, 从而确定summary的答案范围应该是在第二段的最后一句旁边。再一次印证，就算看不懂段落大意，只要按照heading做题思路去看题，那么也是可以帮助确认细节题的答案的。

D段。通过首句的精读，我们会发现是谈论了Medieval Warm Period的特点。该句非常有用，可以帮助确定23到26题的哪道题目可以选C。

E段。针对最后一句的主要内容可以确认该段落在讨论的是食物的供应和自给自足，所以26题当中的fishing patterns定位在该段就相对比较明显。

F段也就是原文的最后一个段落，该段落通过首句只能确认到的信息是Modern Warm Period的情况，但是首尾句精读之后并不能让我们找到比较清楚的heading的答案。所以我们可以先确认23至26题，看细节能否帮助我们确认heading的答案并且同时节约时间不用阅读整个段落。通过24题的trees可以确定答案所在句是在F段的第四句。"The unprecedented land clearance released vast quantities ofcarbon dioxide into the atmosphere, triggering for the first time humanly caused global warming." 同时，该句也可以帮助我们确认F段的heading答案，human impact on the climate。

所以针对上面两篇文章的分析，我们不难得出如下结论：其实先做heading题或者先做细节比较总结或者判断题有各自的利弊。具体来说就是，了解了段落大意有助于细节快速精准的定位，细节的练习可以帮助我们找到某个段落具体在讲什么。

那么让我们再来回到最初的问题，到底是细节先行还是段落大意先飞呢？笔者认为，先按照首二尾句的顺序来完成heading题，一旦我们不能通过简单的这三句话来确认答案的时候，就可以跨题并且仔细记住我们看过的句子的大致意思。不要担心，在你完成细节的时候，heading题的答案也会自然而然浮出水面。