U u (bus) 【short vowel 短母音】

Some more examples(更多例字):
• CVC (子音-母音-子音): cub, dub, hub, nub, pub, rub, sub, tub, mud, bud, bug, dug, hug, jug, lug, mug, pug, rug, tug, bunk, dunk, hunk, junk, chunk, bum, gum, hum, mum, rum, sum, yum, bun, fun, gun, nun, pun, run, sun, cup, pup, sup, Gus, pus, bus, but, cut, gut, hut, jut, nut, rut

• up, us, club, shrub, snub, stub, stud, thud, buff, cuff, huff, puff, bluff, fluff, stuff, chug, drug, thug, plug, slug, smug, snug, such, much, bunch, hunch, lunch, munch, punch, clutch, gush, hush, lush, mush, rush, blush, brush, buck, duck, luck, muck, puck, suck, tuck, yuck, pluck, stuck, truck, struck, dunk, chunk, clunk, trunk, skunk, dusk, husk, musk, tusk, dull, lull, glum, plum, drum, strum, thumb, crumb, shun, spun, stun, lung, rung, bump, dump, hump, jump, lump, pump, clump, slump, stump, plus, thus, hunt, blunt, fuss, bust, dust, gust, just, must, rust, crust, trust, shut, butt, fuzz, under, umbrella, muscle, suffer