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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它的叶子是粗糙和有锯齿的，分为7至9个叶片。

The leaves are coarse and toothed, divided into 7 to 9 leaflets.

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