U字开头的单词或词组
unassignedUAubiquityurusumbilicalUFRutterlyunauthorized accessunreliableundueuncheckedunilaterallyUiguruniformedunderstatementU.S.uniformlyup thereunpackingunder attackupbringingup and downurethrautteranceunfitundressedunscrupulousUSSRunturnedupper boundunremarkedusableureaunluckilyunderscoreunremarkableUPIupendunconventionalunanimousundoubtedunwavering