To better understand breathing during sleep, it is, however, helpful to first understand how respiration works in general.

　　題目出現(xiàn)however，表示本句為轉(zhuǎn)折句。轉(zhuǎn)折句出現(xiàn)表示前后文應(yīng)該出現(xiàn)論述重點的不同，較多出現(xiàn)的情況為后文反駁前文，較少出現(xiàn)的情況也會表示后文開始論述與前文不完全相同的另一個內(nèi)容。

　　根據(jù)插入句的句意“然而，為了更好理解睡眠中的呼吸，先搞清楚平時是如何呼吸是很有幫助的”，可以推斷出本句具有明顯的承上啟下的作用，承接上文論述的“睡眠中的呼吸”，引起下文所述的“平時是如何呼吸的”。根據(jù)推斷尋找后，發(fā)現(xiàn)C位置符合承上啟下的關(guān)系，即為正確答案。

　　3)信息的重復(fù)

　　還有一些插入句，既不包含指代詞，也不包含邏輯詞。但這類插入句的難度其實并不大。

　　和所有插入句相同，不包含信息詞的插入句也和正確位置的前句或后句存在語義上的聯(lián)系，這個聯(lián)系就是信息的重復(fù)。當(dāng)我們找到原文某一個句子，所述內(nèi)容與插入句內(nèi)容相關(guān)時，再來判斷應(yīng)該把插入句放在這個句子的前面還是后面，就能得到答案了。

　　看一道例題會更清楚。

　　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.

　　插入句并沒有指代詞和邏輯詞出現(xiàn)，只表達(dá)了句意“城市里有著多種多樣的生活和工作”。這個時候，我們直接回原文，尋找哪個句子提到或圍繞“城市里的生活和工作”進(jìn)行論述。發(fā)現(xiàn)原文第二句話“Within the city lived administrators, craftspeople, and merchants.”，其實就是具體的闡述city里的工作都有什么，人們都干嘛，與插入句句意是重復(fù)的。且前面一句話最后提到了secular，暗指的其實就是日常生活和工作。所以A是最合適的位置。

　　前一句話先表達(dá)出“除了政治經(jīng)濟(jì)和宗教活動，cities還有很多日?；顒印保o接著后兩句話先總述“城市中的(日常)生活和工作是多種多樣的”，之后再非常具體的舉例描述都存在什么樣的工作和生活，前后邏輯非常吻合，語意流暢。

　　4)綜合

　　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

　　本句既出現(xiàn)代詞“this”也出現(xiàn)邏輯詞“however”，不過this指代內(nèi)容比較模糊?？梢酝茰y出，前面提到的句意，在插入句中得到了否定(not the case)。其次，根據(jù)however存在的轉(zhuǎn)折和承上啟下的關(guān)系，后文非常有可能展開論述this指代內(nèi)容為何不是真實情況(not the case)。結(jié)合推測，找到C位置的前后，符合這個關(guān)系。前一句話說“如果理論正確，則呼吸二氧化碳多會導(dǎo)致打哈欠增多，呼吸氧氣多會減少打哈欠”，后一句話表示“真實情況是(in fact)，不管是二氧化碳還是氧氣，打哈欠的頻率都是相同的”，所以后一句話就是通過描述真實情況，而對前一句理論所推測和估計的情況起到反駁的作用。

　　4. 記得帶進(jìn)去檢驗哈

　　檢驗指的是前文做題步驟中的第四步：將句子放入，講插入句及前后兩句話連起來通讀一遍，檢驗是否流暢邏輯嚴(yán)謹(jǐn)、語意流暢。

　　這個步驟必不可少，來看一道例題。

　　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.

　　本句出現(xiàn)“moreover”，表示插入句和前文是遞進(jìn)關(guān)系，表示進(jìn)一步的論述。后面出現(xiàn)“other evidence”，指出前面應(yīng)該有某些evidence。句中出現(xiàn)even if的讓步關(guān)系，再結(jié)合句意“此外，其他證據(jù)表明，即使無冰走廊確實存在，它也會缺乏人類居住所必須的資源”，可以推測出，前文的evidence應(yīng)該是在論證“ice-free corridor”不存在，這里才會遞進(jìn)+讓步，表示“即使存在，也…”的句意。根據(jù)這個推測發(fā)現(xiàn)C位置前面一句話指出：Glen Macdonald證明支持“ice-free corridor”存在的信息其實是錯誤的。也就是在暗示“ice-free corridor”不存在，能夠和插入句緊密連接。

　　但萬萬沒有想到的是，C位置后面依舊在論述這種corridor不存在：他非常有力地指出，這種無冰走廊直到之后的時期才出現(xiàn)。并且此句中開頭第一個單詞就是“he”，指代的是前句所論述的Glen Macdonald，而插入句卻并沒有能夠滿足he這個指代的內(nèi)容。所以，插入句應(yīng)該放在D位置，待本段最后兩句話把corridor不存在的事情講完，再出現(xiàn)“moreover”進(jìn)行遞進(jìn)。

　　這個題目告訴我們，不僅需要確認(rèn)某個位置的前文與插入句緊密連接，還要往后看一句，確保萬無一失。

　　以上內(nèi)容已將插入句子題幾乎所有情況都進(jìn)行了論述，并且介紹了針對的解題思路，各位好好消化和吸收哦！

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