STEM与日常科技·英语30篇（7）

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主动降噪耳机如何保护听力

Noise-canceling headphones use microphones to detect incoming sound waves before they reach your ears.
A processor then generates inverse sound waves—equal in amplitude but opposite in phase—to cancel them out.
This active method works best on steady, low-frequency noises like airplane engines or air conditioners.
Higher-pitched sounds, such as voices or alarms, are reduced less effectively but still quieter than normal.
By lowering background noise, users avoid turning up volume excessively to hear music or calls clearly.
Studies show people using ANC headphones listen at average levels 8–12 dB lower than without them.
Battery-powered circuits enable real-time adjustments as environments change—like walking from street to subway.
Combined with passive isolation from earcup design, ANC provides dual-layer hearing protection.
Long-term use at safe volumes helps prevent noise-induced hearing loss, especially among young adults.
Still, they shouldn’t replace hearing protection in extremely loud workplaces like construction sites.

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

Combined with passive isolation from earcup design, ANC provides dual-layer hearing protection. 结合耳罩结构提供的被动隔音，主动降噪形成双重听力保护。
Battery-powered circuits enable real-time adjustments as environments change—like walking from street to subway. 电池供电电路可随环境实时调整，例如从街道走入地铁站时。
Still, they shouldn’t replace hearing protection in extremely loud workplaces like construction sites. 但在建筑工地等极高噪音工作场所，它们不能替代专业听力防护设备。

这篇中文题目最接近哪一句？主动降噪耳机如何保护听力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？主动降噪耳机通过麦克风在声音到达耳朵前探测声波。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） How Noise-Canceling Headphones Protect Hearing How to cook noodles A maths worksheet

Combined with passive isolation from earcup design, ANC provides dual-layer hearing protection.

Combined with passive isolation from earcup design, ANC provides dual-layer hearing protection.

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：Combined with passive isolation from earcup design, ANC provides dual-layer hearing protection.