TPO24 托福阅读Passage2 Breathing During Sleep文本+题目原文+答案解析

Breathing During Sleep

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.

[■] 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.

During NREM (the phase of sleep in which there is no rapid eye movement) breathing becomes deeper and more regular, but there is also a decrease in the breathing rate, resulting in less air being exchanged overall. This occurs because during NREM sleep the automatic, metabolic system has exclusive control over breathing and the body uses less oxygen and produces less carbon dioxide. Also, during sleep the automatic metabolic system is less responsive to carbon dioxide levels and oxygen levels in the blood. Two things result from these changes in breathing control that occur during sleep. First, there may be a brief cessation or reduction of breathing when falling asleep as the sleeper waxes and wanes between sleep and wakefulness and their differing control mechanisms. Second, once sleep is fully obtained, there is an increase of carbon dioxide and a decrease of oxygen in the blood that persists during NREM.

But that is not all that changes. During all phases of sleep, several changes in the air passages have been observed. It takes twice as much effort to breathe during sleep because of greater resistance to airflow in the airways and changes in the efficiency of the muscles used for breathing. Some of the muscles that help keep the upper airway open when breathing tend to become more relaxed during sleep, especially during REM (the phase of sleep in which there is rapid eye movement). Without this muscular action, inhaling is like sucking air out of a balloon—the narrow passages tend to collapse. Also there is a regular cycle of change in resistance between the two sides of the nose. If something blocks the "good" side, such as congestion from allergies or a cold, then resistance increases dramatically. Coupled with these factors is the loss of the complex interactions among the muscles that can change the route of airflow from nose to mouth.

Other respiratory regulating mechanisms apparently cease functioning during sleep. For example, during wakefulnessthere is an immediate, automatic, adaptive increase in breathing effort when inhaling is made more difficult (such as breathing through a restrictive face mask). This reflexive adjustment is totally absent during NREM sleep. Only after several inadequate breaths under such conditions, resulting in the considerable elevation of carbon dioxide and reduction of oxygen in the blood, is breathing effort adjusted. Finally, the coughing reflex in reaction to irritants in the airway produces not a cough during sleep but a cessation of breathing. If the irritation is severe enough, a sleeping person will arouse, clear the airway, then resume breathing and likely return to sleep.

Additional breathing changes occur during REM sleep that are even more dramatic than the changes that occur during NREM. The amount of air exchanged is even lower in REM than NREM because, although breathing is more rapid in REM,it is also more irregular, with brief episodes of shallow breathing or absence of breathing. In addition, breathing during REM depends much more on the action of the diaphragm and much less on rib cage action.

TPO24托福阅读 Passage1Breathing During Sleep 题目

Question 1 of 13: According to paragraph 1, which of the following can be inferred about the diaphragm during sleep?

A. During sleep the diaphragm requires increased movement of the rib cage.

B. The diaphragm helps with breathing as movements of the rib cage decrease during sleep.

C. The diaphragm requires a great amount of pressure to function properly.

D. The diaphragm contributes to the effective functioning of the rib cage.

Question 2 of 13: According to paragraph 2, all of the following are true of the voluntary breathing system EXCEPT:

A. It has its control center in the brain stem.

B. It controls breathing for a number of activities during wakefulness.

C. It is able to bypass the automatic system.

D. It produces an irregular breathing pattern.

Question 3 of 13: The word “exclusive” in the passage is closest in meaning to

A. consistent

B. perfect

C. partial

D. sole

Question 4 of 13: According to paragraph 3, which of the following may occur just before NREM sleep begins?

A. The automatic, metabolic system may increase its dependence on air exchanges.

B. Breathing can stop for a short time as a person falls asleep.

C. An increase in the oxygen level in the blood can occur as sleep becomes fully obtained.

D. The level of carbon dioxide in the blood may drop suddenly.

Question 5 of 13:  What is the author's purpose in stating that inhaling is like sucking air out of a balloon?

A. To refute the argument that additional effort is necessary for breathing during sleep

B. To argue that REM sleep is more important than NREM sleep

C. To illustrate the difficulty of breathing during sleep

D. To illustrate how blockage of narrow passages can be prevented during sleep

Question 6 of 13:  It can be inferred from paragraph 4 that the length of time a given molecule of water remains in a lake

All of the following are mentioned in paragraph 4 as being characteristic of breathing during sleep EXCEPT

A. relaxation of the muscles involved in the respiratory system

B. changes in resistance between the two sides of the nose

C. easier airflow in the passages of the upper airway

D. absence of certain complex muscle interactions

Question 7 of 13:  According to paragraph 5, what happens during NREM sleep when inhaling is difficult?

A. There is an immediate, automatic, adaptive increase in breathing effort.

B. The sleeping person takes several inadequate breaths before the breathing effort is adjusted.

C. The coughing reflex causes the breathing effort to adjust.

D. The airways become cleared as the blood removes irritants.

Question 8 of 13: It can be inferred from paragraph 5 that a very mild irritation during sleep will likely cause the sleeping person to

A. increase the breathing effort

B. wake up and remove the source of irritation

C. cough while still sleeping

D. stop breathing temporarily while still sleeping

Question9 of 13 ： The word “considerable” meaning to

A. significant

B. Steady

C. Usual

D. necessary

Question10 of 13: The word “resume” in the passage is closest in meaning to

A. reduce

B. stop

C. readjust

D. restart

Question11 of 13: Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

A. Because breathing is more shallow and irregular in REM than in NREM, less air is exchanged in REM.

B. Breathing in NREM is less effective than breathing in REM because of irregular episodes of rapid breathing during NREM.

C. Because breathing is more rapid in NREM sleep than in REM sleep, breathing often becomes shallow.

D. Although REM has brief episodes of shallow breathing or lack of breathing, breathing is more rapid than in NREM.

Question 12 of 13: Look at the four squares [■] that indicate where the following sentence could be added to the passage.

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

Where would the sentence best fit? Click on a square to add the sentence to the passage

A. 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. 

B. However, there are many other changes that affect respiration when asleep.

C. During wakefulness, breathing is controlled by two interacting systems. 

D.The first is an automatic, metabolic system whose control is centered in the brain stem. 

Question13 of 13:  Directions: From the seven statements below, select the statements that correctly characterize breathing during wakefulness and those statements that correctly characterize breathing during sleep. 

Two of the answer choices will NOT be used. This question is worth 3 points.

Answer Choices

A. The role of the rib cage increases and the role of the diaphragm decreases.

B. Carbon dioxide in blood rises and oxygen drops.

C. The coughing reflex is extremely complex.

D. A great deal of effort is used for breathing.

E. Upper airways are resistant to colds and allergies.

F. There is a drop in the volume of air that is exchanged.

G.Automatic and voluntary respiratory systems are both involved.

TPO24托福阅读Passage2 Breathing During Sleep 真题解析

Question 1 of 13:

答案：B

解析：以diaphragm做关键词定位至第三句和第四句，提到rib cage运动变少，使得diaphragm更重要，但stomach的压力使得diaphragm工作起来更困难，B是正确答案。A的increased movement of the rib cage和C的需要pressure都与原文相反；D的diaphragm contributes to原文未提及。

Question 2 of 13:

答案：A

解析：此题可以采用排除法。A的centered in brain stem做关键词定位至第一句，但原文提到这个特点是属于automatic，metabolic system的，而voluntary的center是在forebrain，所以A错误，可选；B的a number of activities做关键词定位至倒数第二句的一大堆活动，所以B正确，不选；C的bypass the automatic system和D的irregular breathing pattern做关键词都定位至最后一句，都正确，不选。

Question 3 of 13: 

答案：D

解析：exclusive“仅有，只有，排他”，所以正确答案是sole。原句提到在NREM期间，automatic系统怎么控制breathing，使得氧的需求量减少，前面一直在说两个系统，现在氧的需求量减少了，肯定是有系统不干活了，所以就是只有automatic在干活，所以答案是D“只有”。A“持续”B“完美”都不合文意，C的partial刚好与原文意思相反，也不选。

Question 4 of 13: 

答案：B

解析：此题关键词难找，可以顺序向下看，会看到第一点说的是当sleeper在睡与醒之间摇摆的时候，发生了呼吸cessation，也就是stop，所以正确答案是B，stop for a short time。C和D一个说氧上升一个说二氧化碳下降，是同一回事，都不是在睡觉期间发生的，所以都与原文相反，而且两个一样的也都不选，A未提及。

Question 5 of 13:

答案：C

解析：修辞目的题，先看修辞点所在的句子，但原句整个都是一个例子，往前看。前一句仍然在说肌肉relax的事情，因此也是例子，所以看开头，开头提到air passage在睡觉期间变了很多，紧接着就解释睡觉期间呼吸很难，也就是开头所指的，变化是睡觉的时候呼吸变难，所以正确答案是C。A的refute与原文相反；B的比较和D的prevent blockage原文都未提及。

Question 6 of 13:

答案：C

解析：此题可以采用排除法。A的relaxation of the muscles做关键词定位至第三句，正确，不选；B的two sides of the nose做关键词定位至倒数第三句，正确，不选；C的upper airway做关键词定位至第三句，但选项中的easier airflow原文完全未提及，C错误，选；D的complex muscle interaction做关键词都定位至最后一句，正确，不选。

Question 7 of 13:

答案：B

解析：以inhaling is difficult做关键词定位至第二句，但这句只提到了difficult，没提到发生了什么，往下看。下句说NREM期间什么adjustment都没有，只有在inadequate breaths之后才adjust，所以答案是B。A是wakeful时候才有的；C的因果关系原文未提及；D完全未提及。

Question 8 of 13:

答案：D

解析：以irritation做关键词定位至最后一句，提到如果irritation太严重，睡着的人就会醒，按照正常的叙述顺序应该是先叙述mild的情况，前一句说coughing reflex没产生cough，而产生了cessation of breathing，呼吸停止的状况，所以答案是D。C与原文相反；B是severe的时候才有的，A未提及。

Question 9 of 13:

答案：A

解析：considerable“相当大的，重要的”，所以正确答案是significant。原文提到在若干次inadequate breaths之后，二氧化碳含量 上升，氧气含量下降，才能调整breathing，所以答案A在这里意思也是符合的，其他答案都不合文意。

Question 10 of 13:

答案：D

解析：resume“重新开始，再继续”，所以正确答案是restart。原句提到如果irritation太严重了，睡着的人会醒来，清理呼吸道，并且怎么呼吸，前一句说了因为irritants呼吸停止，然后醒来，当然清理完就重新呼吸，答案是D。A和B完全不合文意，如果选C，之前应该adjust一次，但之前从来没提到irritation严重的时候有先调整一次，所以C错误。

Question 11 of 13:

答案：A

解析：原句的结构是air exchanged是因为……，所以正确答案是A，因果关系和结构都正确。其他答案都没提到exchange lower这个主干，而且B把原文非主干的部分变成了主干；C结果弄混了；D逻辑关系错误。

Question 12 of 13:

答案：C

解析：两个过渡点，名词respiration和连词however。根据respiration可以初步确定答案是B或者C，但根据however断定B不正确，因为两个however不能连续出现，所以正确答案是C。

Question 13 of 13:

答案：AG/BDF

解析：第一段和第二段在讲wakeful部分，其余在讲sleep部分；A选项对应第一段第三句，属于wakeful部分；B选项对应第五段第四句，二氧化碳多氧少，属于sleep部分；C选项原文没提到reflex复杂，不属于任何一列，不选；D选项对应原文第四段第三句，属于sleep部分；E选项原文未提及，不选；F选项对应原文第六段第二句，属于sleep部分；G选项对应原文第二段首句，属于wakeful部分。

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