degradation of alluvial valley河谷: river valley的: 4次方是 The fourth power of 2 i ...切: correspond to; be close to蚀: lose冲积河谷: aggraded valley; alluvial valley下载手机词典可随时随地查词查翻译关注微信公众号：chachacidian，回复:冲积河谷的切蚀，即可在微信中查询翻译
