十万个为什么·科学启蒙30篇（3）

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彗星为什么会有尾巴

Comets are icy bodies that orbit the Sun in long, stretched-out paths.
When a comet approaches the Sun, its surface warms up and releases gas and dust.
Solar radiation and the solar wind push this material away from the nucleus.
The glowing gas forms an ion tail, which always points directly away from the Sun.
The dust tail curves slightly because tiny particles respond to both sunlight and gravity.
These tails can stretch millions of kilometers but remain extremely thin and faint.
A comet only develops visible tails when it is inside the orbit of Mars.
Once it moves farther out again, the ice freezes solid and the tails vanish.
This process repeats every time the comet returns on its orbital journey.
So the tail isn’t left behind—it’s freshly made each time the comet gets warm.

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

Comets are icy bodies that orbit the Sun in long, stretched-out paths. 彗星是冰质天体，沿狭长轨道绕太阳运行。
This process repeats every time the comet returns on its orbital journey. 每次彗星沿轨道回归时，这一过程都会重复。
Solar radiation and the solar wind push this material away from the nucleus. 太阳辐射和太阳风将这些物质推离彗核。

这篇中文题目最接近哪一句？彗星为什么会有尾巴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？彗星是冰质天体，沿狭长轨道绕太阳运行。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 Comets Have Tails? How to cook noodles A maths worksheet

Comets are icy bodies that orbit the Sun in long, stretched-out paths.

Comets are icy bodies that orbit the Sun in long, stretched-out paths.

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：Comets are icy bodies that orbit the Sun in long, stretched-out paths.