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

　　303. underrun 跑不过 underran underrun

　　304. undersell 抛售 undersold undersold

　　305. underset 暗流 underset underset

　　306. undershoot 进入射程 undershot undershot

　　307. understand 理解 understood understood

　　308. undertake 担任 undertook undertaken

　　309. underwrite 签名 underwrote underwritten

　　310. undo 取消 undid undone

　　311. undraw 拉开 undrew undrawn

　　312. unfreeze 解冻 unfroze unfrozen

　　313. ungird 解带 ungirded, ungirt ungirded, ungirt

　　314. unhang 解除悬挂 unhung unhung

　　315. unknit 拆开 unknitted, unknit unknitted, unknit

　　316. unlade 卸载 unladed unladed, unladen

　　317. unlay 松开 unlaid unlaid

　　318. unlearn 忘却 unlearnt, unlearned unlearnt, unlearned

　　319. unmake 恢复原状 unmade unmade

　　320. unreeve 抽出 unrove, unreeved unrove, unreeved

　　321. unsay 撤销 unsaid unsaid

　　322. unset 去除设定 unset unset

　　323. unsling 取去悬索 unslung unslung

　　324. unspeak 缄默 unspoke unspoken

　　325. unstick 扯开 unstuck unstuck

　　326. unstring 去掉绑扎 unstrung unstrung

　　327. unswear 毁弃誓言 unswore unsworn

　　328. unteach 使人忘却 untaught untaught

　　329. unthink 打消念头 unthought unthought

　　330. untread 折回 untrod untrodden, untrod

　　331. unweave 拆解 unwove unwoven

　　332. unwind 打开 unwound unwound

　　333. upbuild 在上面建 upbuilt upbuilt

　　334. upcast 上抛 upcast upcast

　　335. uphold 赞成 upheld upheld

　　336. uppercut 上击 uppercut uppercut

　　337. uprise 起义 uprose uprisen

　　338. upset 颠覆 upset upset

　　339. upsweep 向上弯曲 upswept upswept

　　340. upswing 跃进 upswung upswung