托福阅读事实信息题是阅读考试中比较常见的一种题型，tpo则是托福阅读备考最权威的材料，所以托福小编综合二者，为大家集中整理了tpo阅读中考察的事实信息题及其对应的解析，供大家参考使用。本文带来的是TPO24-2的事实信息题，一起来看看吧。
TPO24-2 Breathing During Sleep
paragraph 3
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.
4. 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.
解析：此题关键词难找，可以顺序向下看，也可以用排除法，如果顺序向下看的话，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，是一回事，都不是在睡觉期间发生的，所以都反了，而且两个一样的也都不选，A没说
【3】在NMER(睡觉时没有快速眼部活动的阶段)这个阶段中，呼吸会变得更深更有规律，但是呼吸频率会降低，导致总体空气交换减少。发生这个是因为在NREM睡眠阶段中，自动的新陈代谢系统会独自控制呼吸，身体会利用更少的氧气产生更少的二氧化碳。同时，自动的新陈代谢系统对血液中二氧化碳和氧气的含量反应并不灵敏。在睡眠中呼吸控制的变化会导致两个结果。第一，睡着时呼吸可能会有短暂的停止或减少，因为睡眠者在睡眠和清醒之间徘徊，而这两种状态的控制系统不一样。第二，一旦得到了充足的睡眠，血液中二氧化碳含量升高而氧气含量降低，在NREM阶段也会持续这样。
paragraph 5
Other respiratory regulating mechanisms apparently cease functioning during sleep. For example, during wakefulness there 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.
7. 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.
解析：以inhaling is difficult做关键词定位至第二句，但这句只说了difficult的事儿，没说发生了什么，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的因果关系原文没说;D完全没说
【5】其他呼吸调节机制在睡眠时显然要停止运作。比如说，在清醒时如果呼吸变得困难的话就会有一个立即自动适应性的呼吸增强(比如戴上面具呼吸)。但在NREM状态时完全不存在这样反射性的调节。在这种情况下，只有几次不充分的呼吸后使得血液中二氧化碳的含量显著提升以及氧气的含量降低，呼吸才会被调整过来。最后，咳嗽反应在应对呼吸道中刺激物时产生的不是睡觉时咳嗽而是呼吸停止。如果刺激物足够严重，睡着的人会醒来清理气道，然后继续呼吸很可能再度入睡。
以上就是托福阅读TPO24-2中的事实信息题及其解析，大家可以在备考的时候参考复习，希望能够帮助大家的考前准备。最后前程百利祝大家都能取得理想的托福考试成绩。
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