U字开头的单词或词组
UPSupchuckUNIXundertakingunrelatedunsuspectedupstartupper caseUnicodeunevenuntrueunfavourableuncouthunaccustomedunsteadyuric aciduninterruptedunfaithfulunderwaterunspoiltunconsciouslyusurpunmatchuneventfulultramarineULFunregisteredunconditionalunbalancedunsungunidentifiedunfilledunilateralunbrokenundefined variableU.S.S.R.unidentified flying objectuglinessukuleleunsureunresolvedupkeep
