U字開頭的單詞或詞組
undoubtedlyupstairsup-to-dateustinunableU-turnunfortunatelyunexpectedlyunitaryunrecognized commandusingultimatelyuncertaintyunderlyingup to dateUFOuntitledU.K.unlessUnited Nationsuptakeurnunder wayUSAupside downubiquitousundermineunblockuncertainunityunderstandinguserunpackUNOumpunzipupsideuselessUHFundertakeunauthorizedunwilling