U字開(kāi)頭的單詞或詞組
underreportusual practiceUMBuninhabitableunmaskup one's streetUMAunder footup the riverunpickunit numberunstructuredunfeasibleundockUnion of Soviet Socialist Republicsuracilup-and-downunintendedultrasonographyunfaithfulundercoatuncloudeduntrustworthyunderwriteunburdenuniversal machineuveitisunsetunobtrusiveundercurrentuglilyupholsteryupliftedunderwoodup onunmistakableU.S.A.unadjustedunclaimedunattractiveunmatchableunrivaled