短語詞組短語river bed protection material 護底結構型式seed bed base material 苗床基質(zhì)fluidized bed combustion material 流態(tài)化材料filter bed doubledeck material 雙層濾料濾池bed d material load 底部物質(zhì)負荷bed -material load 底負載bed of material 料層 返回 bed material