Present participle; Past participle - whitening - whitened Present - whiten - whiten - whitens - whiten - whiten - whiten Past - whitened - whitened - whitened - whitened - whitened - whitened Future - will whiten - will whiten - will whiten - will whiten - will whiten - will whiten Present conditional - would whiten - would whiten - would whiten - would whiten - would whiten - would whiten Present Perfect - have whitened - have whitened - has whitened - have whitened - have whitened - have whitened Past Perfect - had whitened - had whitened - had whitened - had whitened - had whitened - had whitened Future Perfect - will have whitened - will have whitened - will have whitened - will have whitened - will have whitened - will have whitened Past conditional - would have whitened - would have whitened - would have whitened - would have whitened - would have whitened - would have whitened Imperative - - - whiten - - - - - - - -