托福阅读长难句分析（47）

　　According to conventional theory, yawning takes place when people are bored or sleepy and serves the function of increasing alertness by reversing, through deeper breathing, the drop in blood oxygen levels that are caused by the shallow breathing that accompanies lack of sleep or boredom.(TPO18, 45)

　　conventional /kən'vɛnʃənl/ adj. 传统的;老套的，千篇一律的;约定的

　　alertness /ə'lə:tnis/ n. 警戒，机敏

　　reverse /rɪ'vɜːs/ v. 使(某物)反转; 将(某物)翻转;转变

　　我是分界线，大家先一遍速读看是否理解

　　(According to conventional theory), yawning takes place (when people are bored or sleepy)and serves the function (of increasing alertness) (by reversing, through deeper breathing, the drop in blood oxygen levels) (that are caused by the shallow breathing) (that accompanies lack of sleep or boredom).(TPO18, 45)

　　托福阅读长难句100句分析：

　　这个句子的主干就是：

　　yawning takes place and serves the function

　　修饰一：(According to conventional theory)，介词短语

　　中文：根据传统理论

　　修饰二：(when people are bored or sleepy)，从句

　　中文：当人们感到厌烦或困倦时

　　修饰三：(of increasing alertness)，介词短语

　　中文：增强警觉

　　修饰四：(through deeper breathing)，插入语

　　中文：通过深呼吸