The waves reflect different kinds of rocks under the surface. Hard or dense rocks reflect more strongly than soft or porous ones; and the time lag of waves can indicate the depth of the reflecting layer.是什么意思_The waves reflect different kinds of rocks under the surface. Hard or dense rocks reflect more strongly than soft or porous ones; and the time lag of waves can indicate the depth of the reflecting layer.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句