roughage

n [U] indigestible material in certain plants used as food (eg bran) that stimulates the action of the intestines, and helps the digestion of other foods 粗糙食物（不易吸收的粗纤维, 如糠、 麸, 可刺激肠蠕动, 有助於消化他种食物）.

rote, rote learning, rotisserie, rotor, rotten, rottenly, rottenness, rotter, rotund, rotunda, rotundity, rotundly, rouble (also ruble), roue, rouge, rough, rough house, rough luck, rough-and-tumble, rough-hewn, roughcast, roughen, roughly, roughneck, roughness, roughshod, roulette, round, round and round, round brackets, round off, round robin, round trip, round up, round-eyed, round-shouldered, round-table, round-up, roundabout, rounded,