托福阅读插入句子题答题技巧
这种题长这样：
Paragraph 8: Much of the water in a sample of water-saturated sediment or rock will drain from it if the sample is put in a suitable dry place. █But some will remain, clinging to all solid surfaces. █It is held there by the force of surface tension without which water would drain instantly from any wet surface, leaving it totally dry. █The total volume of water in the saturated sample must therefore be thought of as consisting of water that can, and water that cannot, drain away. █
13. Look at the four squares [█] that indicate where the following sentence could be added to the passage.
What, then, determines what proportion of the water stays and what proportion drains away?
Where would the sentence best fit?
怎么做插入句子题?
题目给出的句子(后文直接称之为“插入句”)能被放入其中一个位置的原因，就是这个句子与正确位置的前后文存在着某种语义上的联系。在阅读原文之前，若能根据一些信息词找出这种联系，并且推测前后文的信息，则我们在找答案的时候就会更准确。
做插入句子题时的步骤应该是酱紫的：
1)仔细阅读插入句，准确理解句意
2)根据句内信息词，推断插入位置前或后可能出现的内容
3)寻找复合推测的位置
4)将句子放入，讲插入句及前后两句话连起来通读一遍，检验是否流畅逻辑严谨、语意流畅
3. 信息词是啥?如何根据这类词推测?
插入句子题中出现的信息词分两类：1. 代词;2. 逻辑词
1)指代词
这里的指代词指的是：1. 代词;2. 定冠词the+名词所组成词。
代词(Pronoun)是代替名词或一句话的一种词类。the+名词的结构，在文中有时会起指代前文的作用。大部分出现指代词的插入句子题非常简单。
当题目的句子中出现指代词，插入位置前面必然会提到其指代的内容。这个时候，若我们能根据代词的种类、指代词的词义和插入句的句意推断出指代的具体内容，那么只需要将插入句放入出现该内容的句子之后的位置，即可满足指代关系，得到答案
# 情况1
如果四个位置中，只有一个位置前面出现句中指代词的指代对象，则这个位置就是我们的正确答案。
例题如下：
At times, it is actually possible to watch the effects of natural selection in host-parasite relationships. For example, Australia during the 1940 s was overrun by hundreds of millions of European rabbits. █ The rabbits destroyed huge expanses of Australia and threatened the sheep and cattle industries. █ In 1950, myxoma virus, a parasite that affects rabbits, was deliberately introduced into Australia to control the rabbit population. █ Spread rapidly by mosquitoes, the virus devastated the rabbit population. █ The virus was less deadly to the offspring of surviving rabbits, however, and it caused less and less harm over the years. Apparently, genotypes (the genetic make-up of an organism) in the rabbit population were selected that were better able to resist the parasite. Meanwhile, the deadliest strains of the virus perished with their hosts as natural selection favored strains that could infect hosts but not kill them. Thus, natural selection stabilized this host-parasite relationship.
This massive population began a century earlier as a mere twelve pairs of imported rabbits that reproduced quickly and developed into a major problem.
句中出现代词“this massive population”，这巨大的群体数量来自于“twelve pairs of imported rabbits”，则插入位置前面必然提到巨大的兔群数量。
只有第一个位置前面的句子提到“hundreds of millions of European rabbits”，可以构成指代的对象。所以A就是妥妥的正确答案。
# 情况2(较少出现)
如果四个位置中有多个位置的前面存在着“可能成为”指代词的指代对象的信息，那么往往只有其中一个内容能够符合指代词的`“特性”。
例题如下：
While some European countries, such as England and Germany, began to industrialize in the eighteenth century, the Netherlands and the Scandinavian countries of Denmark, Norway, and Sweden developed later. █ All four of these countries lagged considerably behind in the early nineteenth century. █ However, they industrialized rapidly in the second half of the century, especially in the last two or three decades. █ In view of their later start and their lack of coal—undoubtedly the main reason they were not among the early industrializers—it is important to understand the sources of their success. █
During this period, Sweden had the highest rate of growth of output per capita of any country in Europe, and Denmark was second.
句中出现代词“this period”，插入位置前面必然提到某一个时期。同时，我们还要注意，句子还提到，这个时期里Sweden和Denmark经济发展特别好。
原文前三个位置之前的句子都提到了时期，分别是18世纪、19世纪上半叶和19世纪下半叶。然而前两句话所说的时期中，Sweden和Denmark都是处在落后的位置。而第三句话however转折之后的信息提到，19世纪下半叶，尤其是最后二三十年，它们(指的是Netherlands、Denmark、Norway和Sweden)发展特别快。也就是说，19世纪下半叶才是插入句中this period指代的内容，前两个时期都不能复合指代内容的特性。所以C是正确答案。
# 情况3
有些插入句由于代词性质比较特殊，又或对于代词的描述信息较少，故无法直接准确的推测出代词所指的内容，只能得到一个大概的方向。此时需要结合原文句意，逐个位置确认和排除。
例题如下：
The harsh conditions in deserts are intolerable for most plants and animals. Despite these conditions, however, many varieties of plants and animals have adapted to deserts in a number of ways. Most plant tissues die if their water content falls too low: the nutrients that feed plants are transmitted by water; water is a raw material in the vital process of photosynthesis; and water regulates the temperature of a plant by its ability to absorb heat and because water vapor lost to the atmosphere through the leaves helps to lower plant temperatures. █Water controls the volume of plant matter produced. █The distribution of plants within different areas of desert is also controlled by water. █Some areas, because of their soil texture, topographical position, or distance from rivers or groundwater, have virtually no water available to plants, whereas others do.█
For this reason, the total amount of plant material in a desert is often 100 times less than the amount of plant material in an equivalent area of temperate forest.
句中出现“for this reason”，前文所提到的信息导致“相同面积下，desert中的the total amount of plant material比temperate forest中的the total amount of plant material低100倍”。此时并不能直接得出this reason所指信息具体内容，但可知，该reason为插入句的原因，正确位置必然能满足这个因果关系。
找到1、2位置之间的句子“Water controls the volume of plant matter produced.”。其中the volume of plant matter和the total amount of plant material意思相同，其次由于water的控制作用，确实会导致两个水量不同的地区(desert和forest)产生差别，前后逻辑非常严谨，所以B是正确答案。
2)逻辑词
逻辑词仅仅是为了简(zhuang)洁(bi)而起的一个名字，指的是能够表示句间逻辑关系的那些词，如however、but、therefore、also、then等等。
出现这些逻辑词的时候，代表着插入句的句意和其前句或后句在信息上存在着某种逻辑关系。根据找到的逻辑关系，结合插入句的句意，可以大致推测一下前文或后文的句意，以此作为寻找正确答案的指向性信息。
例题1
Less colorful birds and animals that inhabit the rain forest tend to rely on forms of signaling other than the visual, particularly over long distances. █ The piercing cries of the rhinoceros hornbill characterize the Southeast Asian rain forest, as do the unmistakable calls of the gibbons. █ In densely wooded environments, sound is the best means of communication over distance because in comparison with light, it travels with little impediment from trees and other vegetation. █ In forests, visual signals can be seen only at short distances, where they are not obstructed by trees. █ The male riflebird exploits both of these modes of signaling simultaneously in his courtship display. The sounds made as each wing is opened carry extremely well over distance and advertise his presence widely. The ritualized visual display communicates in close quarters when a female has approached.
There is also the long, rather terrifying call of the male orangutan, which carries over considerable distances to advertise his presence.
句中出现“also”，根据句意，可以推测正确位置之前至少会提到与动物相关的某种特性，所以才会紧跟插入句所说的“also有雄性O动物的call”。发现第二个位置前面提到rhinoceros hornbill的叫声cries和gibbons的喊声calls，那么把插入句放到第二个位置，起到了进一步举例说明的作用，满足了also的关系，前后逻辑严谨。
例题2
Paragraph 1: Of all the physiological differences in human sleep compared with wakefulness that have been discovered in the last decade, changes in respiratory control are most dramatic. Not only are there differences in the level of the functioning of respiratory systems, there are even changes in how they function. Movements of the rib cage for breathing are reduced during sleep, making the contractions of the diaphragm more important. █ Yet because of the physics of lying down, the stomach applies weight against the diaphragm and makes it more difficult for the diaphragm to do its job. █ However, there are many other changes that affect respiration when asleep.
Paragraph 2: █ During wakefulness, breathing is controlled by two interacting systems. █The first is an automatic, metabolic system whose control is centered in the brain stem. It subconsciously adjusts breathing rate and depth in order to regulate the levels of carbon dioxide (CO2) and oxygen (O2), and the acid-base ratio in the blood. The second system is the voluntary, behavioral system. Its control center is based in the forebrain, and it regulates breathing for use in speech, singing, sighing, and so on. It is capable of ignoring or overriding the automatic, metabolic system and produces an irregular pattern of breathing.
To better understand breathing during sleep, it is, however, helpful to first understand how respiration works in general.
题目出现however，表示本句为转折句。转折句出现表示前后文应该出现论述重点的不同，较多出现的情况为后文反驳前文，较少出现的情况也会表示后文开始论述与前文不完全相同的另一个内容。
根据插入句的句意“然而，为了更好理解睡眠中的呼吸，先搞清楚平时是如何呼吸是很有帮助的”，可以推断出本句具有明显的承上启下的作用，承接上文论述的“睡眠中的呼吸”，引起下文所述的“平时是如何呼吸的”。根据推断寻找后，发现C位置符合承上启下的关系，即为正确答案。
3)信息的重复
还有一些插入句，既不包含指代词，也不包含逻辑词。但这类插入句的难度其实并不大。
和所有插入句相同，不包含信息词的插入句也和正确位置的前句或后句存在语义上的联系，这个联系就是信息的重复。当我们找到原文某一个句子，所述内容与插入句内容相关时，再来判断应该把插入句放在这个句子的前面还是后面，就能得到答案了。
看一道例题会更清楚。
Paragraph 3: It used to be believed that before 3000 B.C.E. the political and economic life of the cities was centered on their temples, but it now seems probable that the cities had secular rulers from earliest times. █Within the city lived administrators, craftspeople, and merchants. (Trading was important, as so many raw materials, the semiprecious stones for the decoration of the temples, timbers for roofs, and all metals, had to be imported.) █An increasingly sophisticated system of administration led in about 3300 B.C.E. to the appearance of writing. █The earliest script was based on logograms, with a symbol being used to express a whole word. █The logograms were incised on damp clay tablets with a stylus with a wedge shape at its end. (The Romans called the shape cuneus and this gives the script its name of cuneiform.) Two thousand logograms have been recorded from these early centuries of writing. A more economical approach was to use a sign to express not a whole word but a single syllable. (To take an example: the Sumerian word for " head” was “sag.” Whenever a word including a syllable in which the sound “sag” was to be written, the sign for “sag" could be used to express that syllable with the remaining syllables of the word expressed by other signs.) By 2300 B.C.E. the number of signs required had been reduced to 600, and the range of words that could be expressed had widened. Texts dealing with economic matters predominated, as they always had done; but at this point works of theology, literature, history, and law also appeared.
City life was diverse, and the population was engaged in a variety of occupations.
插入句并没有指代词和逻辑词出现，只表达了句意“城市里有着多种多样的生活和工作”。这个时候，我们直接回原文，寻找哪个句子提到或围绕“城市里的生活和工作”进行论述。发现原文第二句话“Within the city lived administrators, craftspeople, and merchants.”，其实就是具体的阐述city里的工作都有什么，人们都干嘛，与插入句句意是重复的。且前面一句话最后提到了secular，暗指的其实就是日常生活和工作。所以A是最合适的位置。
前一句话先表达出“除了政治经济和宗教活动，cities还有很多日常活动”，紧接着后两句话先总述“城市中的(日常)生活和工作是多种多样的”，之后再非常具体的举例描述都存在什么样的工作和生活，前后逻辑非常吻合，语意流畅。
4)综合
Another flaw of the tiredness theory is that yawning does not raise alertness or physiological activity, as the theory would predict. When researchers measured the heart rate, muscle tension and skin conductance of people before, during and after yawning, they did detect some changes in skin conductance following yawning, indicating a slight increase in physiological activity. However, similar changes occurred when the subjects were asked simply to open their mouths or to breathe deeply. Yawning did nothing special to their state of physiological activity. Experiments have also cast serious doubt on the belief that yawning is triggered by a drop in blood oxygen or a rise in blood carbon dioxide. █Volunteers were told to think about yawning while they breathed either normal air, pure oxygen, or an air mixture with an above-normal level of carbon dioxide. █If the theory was correct, breathing air with extra carbon dioxide should have triggered yawning, while breathing pure oxygen should have suppressed yawning. █In fact, neither condition made any difference to the frequency of yawning, which remained constant at about 24 yawns per hour. █Another experiment demonstrated that physical exercise, which was sufficiently vigorous to double the rate of breathing, had no effect on the frequency of yawning Again the implication is that yawning has little or nothing to do with oxygen.
This, however, was not the case
本句既出现代词“this”也出现逻辑词“however”，不过this指代内容比较模糊。可以推测出，前面提到的句意，在插入句中得到了否定(not the case)。其次，根据however存在的转折和承上启下的关系，后文非常有可能展开论述this指代内容为何不是真实情况(not the case)。结合推测，找到C位置的前后，符合这个关系。前一句话说“如果理论正确，则呼吸二氧化碳多会导致打哈欠增多，呼吸氧气多会减少打哈欠”，后一句话表示“真实情况是(in fact)，不管是二氧化碳还是氧气，打哈欠的频率都是相同的”，所以后一句话就是通过描述真实情况，而对前一句理论所推测和估计的情况起到反驳的作用。
4. 记得带进去检验哈
检验指的是前文做题步骤中的第四步：将句子放入，讲插入句及前后两句话连起来通读一遍，检验是否流畅逻辑严谨、语意流畅。
这个步骤必不可少，来看一道例题。
Paragraph 1: It has long been accepted that the Americas were colonized by a migration of peoples from Asia, slowly traveling across a land bridge called Beringia (now the Bering Strait between northeastern Asia and Alaska) during the last Ice Age. █The first water craft theory about the migration was that around 11,000-12,000 years ago there was an ice-free corridor stretching from eastern Beringia to the areas of North America south of the great northern glaciers. It was the midcontinental corridor between two massive ice sheets-the Laurentide to the west-that enabled the southward migration. █But belief in this ice-free corridor began to crumble when paleoecologist Glen MacDonald demonstrated that some of the most important radiocarbon dates used to support the existence of an ice-free corridor were incorrect. █He persuasively argued that such an ice-free corridor did not exist until much later, when the continental ice began its final retreat. █
Moreover, other evidence suggests that even if an ice-free corridor did exist, it would have lacked the resources needed for human colonization.
本句出现“moreover”，表示插入句和前文是递进关系，表示进一步的论述。后面出现“other evidence”，指出前面应该有某些evidence。句中出现even if的让步关系，再结合句意“此外，其他证据表明，即使无冰走廊确实存在，它也会缺乏人类居住所必须的资源”，可以推测出，前文的evidence应该是在论证“ice-free corridor”不存在，这里才会递进+让步，表示“即使存在，也…”的句意。根据这个推测发现C位置前面一句话指出：Glen Macdonald证明支持“ice-free corridor”存在的信息其实是错误的。也就是在暗示“ice-free corridor”不存在，能够和插入句紧密连接。
但万万没有想到的是，C位置后面依旧在论述这种corridor不存在：他非常有力地指出，这种无冰走廊直到之后的时期才出现。并且此句中开头第一个单词就是“he”，指代的是前句所论述的Glen Macdonald，而插入句却并没有能够满足he这个指代的内容。所以，插入句应该放在D位置，待本段最后两句话把corridor不存在的事情讲完，再出现“moreover”进行递进。
这个题目告诉我们，不仅需要确认某个位置的前文与插入句紧密连接，还要往后看一句，确保万无一失。
以上内容已将插入句子题几乎所有情况都进行了论述，并且介绍了针对的解题思路，各位好好消化和吸收哦!
