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为什么冰能浮在水面上？这对生命有多重要？

Ice floats because water expands when it freezes, becoming about 9% less dense than liquid water.
This unusual behavior results from hydrogen bonds arranging into open hexagonal lattices as temperature drops.
Most substances contract and sink when solidifying, but water’s density peaks at 4°C before decreasing.
Floating ice forms an insulating layer that protects aquatic life beneath from complete freezing.
Without this property, lakes and oceans would freeze solid from the bottom up, killing most ecosystems.
Seasonal ice cover also regulates global climate by reflecting sunlight back into space.
Polar bears, seals, and algae all depend on stable sea ice platforms for hunting and reproduction.
Glaciers move slowly because basal ice melts under pressure, lubricating their slide over bedrock.
Engineers mimic ice’s low-density structure to design lightweight, strong aerogel materials.
If water behaved like most liquids, Earth might never have developed complex multicellular life.

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

Engineers mimic ice’s low-density structure to design lightweight, strong aerogel materials. 工程师模仿冰的低密度结构，设计出轻质高强的气凝胶材料。
Seasonal ice cover also regulates global climate by reflecting sunlight back into space. 季节性海冰覆盖还能通过反射阳光调节全球气候。
Floating ice forms an insulating layer that protects aquatic life beneath from complete freezing. 漂浮的冰层起到隔热作用，保护下方水生生物免遭完全冻结。

这篇中文题目最接近哪一句？为什么冰能浮在水面上？这对生命有多重要？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？冰能漂浮，是因为水结冰时体积膨胀，密度比液态水低约9%。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 Does Ice Float—And Why Is That So Important for Life? How to cook noodles A maths worksheet

Engineers mimic ice’s low-density structure to design lightweight, strong aerogel materials.

Engineers mimic ice’s low-density structure to design lightweight, strong aerogel materials.

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：Engineers mimic ice’s low-density structure to design lightweight, strong aerogel materials.