Present participle; Past participle - massing - massed Present - mass - mass - masses - mass - mass - mass Past - massed - massed - massed - massed - massed - massed Future - will mass - will mass - will mass - will mass - will mass - will mass Present conditional - would mass - would mass - would mass - would mass - would mass - would mass Present Perfect - have massed - have massed - has massed - have massed - have massed - have massed Past Perfect - had massed - had massed - had massed - had massed - had massed - had massed Future Perfect - will have massed - will have massed - will have massed - will have massed - will have massed - will have massed Past conditional - would have massed - would have massed - would have massed - would have massed - would have massed - would have massed Imperative - - - mass - - - - - - - -