5. 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 覺得比喻很怪 因為文章前面是在強調muscle清醒時能保持upper airway暢通 睡著時muscle會很放鬆(尤其是REM時) 所以upper airway應該是會塌下來而造成呼吸困難才對 但原文是說 Without this muscular action, inhaling is like sucking air out of a balloon— the narrow passages tend to collapse. 這個比喻應該是說進氣量太大會導致upper airway崩潰? 雖然答案選對了， 但還是不懂為什麼呼吸困難==上呼吸道崩潰? 而且會崩潰應該是說muscle沒有維持住呼吸道的大小 但文章只提到muscles help keep the upper airway open 沒有說進氣量過大muscle會幫忙維持啊? 看了很多次還是覺得這句話很奇怪 請問有大大能夠幫忙解答嗎? 附上原文網站：https://toeflv3.kmf.com/detail/252hjk.html --

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