十万个为什么·科学启蒙30篇（1）

21 / 30

已读 0 / 30 课

为什么我们在疲倦或无聊时打哈欠？

Yawning opens your mouth wide and pulls in a large breath of cool air.
This extra oxygen may help wake up your brain and improve alertness slightly.
Brain temperature rises when you're tired, and yawning cools it via blood flow.
Contagious yawning happens because mirror neurons fire when we see others yawn.
Children under five rarely catch yawns, suggesting social development matters.
Even dogs yawn after watching humans, showing empathy may be involved.
Yawning occurs in fetuses before birth, so it’s partly built-in, not learned.
It stretches jaw muscles and increases heart rate for short bursts of energy.
Some scientists think it prepares the body for transitions—like waking or sleeping.
Though common, no single theory fully explains all yawning behavior yet.

听 → 读 → 学表达 → 懂 → 今天会说这一句 → 跟读录音 → 自己说一句。

Children under five rarely catch yawns, suggesting social development matters. 五岁以下儿童极少被传染打哈欠，表明这与社会性发展有关。
Even dogs yawn after watching humans, showing empathy may be involved. 狗看到人类打哈欠后也会打哈欠，暗示其中可能存在共情作用。
Though common, no single theory fully explains all yawning behavior yet. 尽管很常见，目前尚无单一理论能完全解释所有打哈欠行为。

这篇中文题目最接近哪一句？为什么我们在疲倦或无聊时打哈欠？一次学校运动会的通知一份超市购物清单

课文第一句的意思更接近？打哈欠会张大嘴巴，吸入一大口凉气。今天学校放假了。请把窗户打开。

这一课主要在讲什么？（看英文标题） Why Do We Yawn When We’re Tired or Bored? How to cook noodles A maths worksheet

Children under five rarely catch yawns, suggesting social development matters.

Children under five rarely catch yawns, suggesting social development matters.

第一版：录下来、回听、再听标准音。系统打分以后再加。

用今天的表达，自己说一句。

例子：Children under five rarely catch yawns, suggesting social development matters.