U字开头的单词或词组
unclaimedup-and-downuprootunit vectorUBundockunder the control ofupliftedunjustifiedunderreportunsightlyUnion of Soviet Socialist Republicsunattractiveunmatchableutility powerundulyunderwritingunendingunderwoodunder footultrasonographyunadjustedunder the guidance of...unwittingultimate designunburdenup the riverupset stomachunaffectedunfeasibleunshakenuninvitedunit numberunmarriedunorthodoxurinary bladderunwieldyurinalunearthlyunfreezeuninhabitableupholstery
