1. Those produce a large number of faint reflections in what's called as: a smooth of echo. 这些（松针并不茂密的松树）能产生大量微弱的反射，我们称之为“平滑回声”。
2. Those private reflections may have historical significance long after the author's death. 这些个人反思在作者死后很长一段时间内可能仍具有重要历史意义。
3. So, the echoes from a tree are going to a mass of chaotic acoustic reflections, not like the echo from a moth. 所以，树的回声会是一团混乱的声波反射，而不像飞蛾的回声那样。
4. The large satellites interfere more seriously with telescope observations because of the strong reflections they produce. 由于大型卫星产生的强烈反射，它们对望远镜观测的干扰更为严重。
5. But an oak which has fewer but bigger leaves with stronger reflections, produces a jagged wave form, or what we called a rough echo. 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”。
