ripple

n.涟漪，波纹

rink, rinse, Rio de Janneiro, riot, riot police, riot shield, riotous, riotously, riotousness, rip, rip-cord, rip-off, rip-roaring, rip-saw, rip-tide, riparian, ripe, ripen, ripeness, riposte, rise, rise superior to, riser, risible, rising, rising damp, rising fives, risk, riskily, riskiness, risky, risotto, risque, rissole, rite, ritual, ritualize, ritzy, rival, rivalry,