U字开头的单词或词组
unfaithfulunconsciouslyunevenunsuspectedunrelatedundertakingunwantedupchuckUNIXupstartuntrueupper caseuninterruptedUnicodeuncouthunfavourableunaccustomedunsteadyuric acidunderwaterunregisteredunspoiltuneventfulusurpunmatchunidentifiedultramarineunsungULFunbalancedunconditionalunbrokenunsureunilateralunfilledU.S.S.R.undefined variableuttererunidentified flying objectuglinessukuleleunresolved
