Chōng / jī / shàn / shì / hé / liú / zài / chū / shān / kǒu / chù / duī / jī / ní / shā / xíng / chéng / de / dì / xíng冲积扇是河流在出山口处堆积泥沙形成的地形。An alluvial fan is a landform formed by rivers depositing sediment at mountain exits.