rapids

n. 急流，湍流

rani, rank, ranking officer, rankle, rankly, rankness, ransack, ransom, rant, ranter, rap, rapacious, rapaciously, rapacity, rape, rapid, rapid transit, rapid-fire, rapidity, rapidly, rapier, rapier-thrust, rapine, rapist, rapport, rapprochement, rapscallion, rapt, raptly, rapture, rapturous, rapturously, rare, rare earth, rarebit, rarefaction, rarefied, rarefy, rarely, rareness,