kē xué jiā / tōng guò / guān chá / yán céng / yán jiū / le / gǔ dài / làng shí / liú xià / de / hén jì

科学家通过观察岩层，研究了古代浪蚀留下的痕迹。

By observing rock layers, scientists studied the traces left by ancient wave erosion.