但是，橡树的叶子少而又大，反射力较强，会产生参差不齐的声波，或所谓的“粗糙回声”。

But an oak which has fewer but bigger leaves with stronger reflections, produces a jagged wave form, or what we called a rough echo.

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这些蝙蝠能够区分这两种声音，不仅仅是通过树木的回声，而是通过任何平滑或粗糙的回声。

These bats can distinguish between the two, and not just with trees, but with any echo that comes in a smooth or rough shape.

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