Present participle; Past participle - requiring - required Present - require - require - requires - require - require - require Past - required - required - required - required - required - required Future - will require - will require - will require - will require - will require - will require Present conditional - would require - would require - would require - would require - would require - would require Present Perfect - have required - have required - has required - have required - have required - have required Past Perfect - had required - had required - had required - had required - had required - had required Future Perfect - will have required - will have required - will have required - will have required - will have required - will have required Past conditional - would have required - would have required - would have required - would have required - would have required - would have required Imperative - - - require - - - - - - - -