Present participle; Past participle - sickening - sickened Present - sicken - sicken - sickens - sicken - sicken - sicken Past - sickened - sickened - sickened - sickened - sickened - sickened Future - will sicken - will sicken - will sicken - will sicken - will sicken - will sicken Present conditional - would sicken - would sicken - would sicken - would sicken - would sicken - would sicken Present Perfect - have sickened - have sickened - has sickened - have sickened - have sickened - have sickened Past Perfect - had sickened - had sickened - had sickened - had sickened - had sickened - had sickened Future Perfect - will have sickened - will have sickened - will have sickened - will have sickened - will have sickened - will have sickened Past conditional - would have sickened - would have sickened - would have sickened - would have sickened - would have sickened - would have sickened Imperative - - - sicken - - - - - - - -