Present participle; Past participle - shelling - shelled Present - shell - shell - shells - shell - shell - shell Past - shelled - shelled - shelled - shelled - shelled - shelled Future - will shell - will shell - will shell - will shell - will shell - will shell Present conditional - would shell - would shell - would shell - would shell - would shell - would shell Present Perfect - have shelled - have shelled - has shelled - have shelled - have shelled - have shelled Past Perfect - had shelled - had shelled - had shelled - had shelled - had shelled - had shelled Future Perfect - will have shelled - will have shelled - will have shelled - will have shelled - will have shelled - will have shelled Past conditional - would have shelled - would have shelled - would have shelled - would have shelled - would have shelled - would have shelled Imperative - - - shell - - - - - - - -