U字开头的单词或词组
UMBunceasinguninhabitableunmaskup one's streetusual practiceunder footunit numberunpickunfeasibleunstructuredundockup-and-downuracilultrasonographyunburdenUnion of Soviet Socialist Republicsuntrustworthyundetecteduniversal machineunderwriteuncloudeduveitisUMAundercoatundercurrentup onunobtrusiveupholsteryupliftedunattractiveunmatchableunderwooduglilyunfaithfulU.S.A.unadjustedunsetunimpressedunderwritingupdate informationundivided
