【轻松英文阅读】我们为什么会打哈欠

 First, let's start by busting¹ one myth about yawning. A lot of people have the misconception that we yawn because our brains need more oxygen. However, several studies have shown that no matter how little oxygen is around a person, they won't yawn more. Even after exercise, when people in fact do need more oxygen, they do not yawn more frequently. Recent research says that the answer does lie in the brain, but that it is not a lack of oxygen , but rather it is because of the temperature of the brain. When we are exhausted² the temperature deep in the brain increases. However, the brain operates best at a specific temperature, much like a computer. When you yawn, you bring in a lot of air from the outside into your mouth and ears. This air cools down the blood in your face and that helps cool down your brain. So yawning helps us to regulate our brain’s temperature.

 

This article is a summary of a video report from Vsauce. 

1 busting   

打破，打碎( bust的现在分词 )； 突击搜查（或搜捕）； （使）降级，降低军阶

参考例句：

• Jim and his wife were busting up again yesterday. 吉姆和他的妻子昨天又吵架了。
• He figured she was busting his chops, but it was all true. 他以为她在捉弄他，其实完全是真的。

2 exhausted   

adj.极其疲惫的，精疲力尽的

参考例句：

• It was a long haul home and we arrived exhausted.搬运回家的这段路程特别长，到家时我们已筋疲力尽。
• Jenny was exhausted by the hustle of city life.珍妮被城市生活的忙乱弄得筋疲力尽。