river bed

n.河床

risible, rising, rising damp, rising fives, risk, riskily, riskiness, risky, risotto, risque, rissole, rite, ritual, ritualize, ritzy, rival, rivalry, rive, riven, river, river-bed, riverside, rivet, riveter, riveting, Riviera, rivulet, riyal, rly, RM, RN, RNA, RNIB, RNLI, roach, road, road safety, road sense, road show, road tax,