291. unbind 解开 unbound unbound
292. unbuild 拆除 unbuilt unbuilt
293. underbid 出低价 underbid underbidden, underbid
294. underbuy 贱价买走 underbought underbought
295. undercut 廉价出售 undercut undercut
296. underdo 不尽力 underdid underdone
297. underfeed 喂不饱 underfed underfed
298. undergo 遭受 underwent undergone
299. underlay 铺垫 underlaid underlaid
300. underlet 低价出租 underlet underlet
301. underlie 位居其次 underlay underlain
302. underpay 克扣 underpaid underpaid