Present participle; Past participle - trebling - trebled Present - treble - treble - trebles - treble - treble - treble Past - trebled - trebled - trebled - trebled - trebled - trebled Future - will treble - will treble - will treble - will treble - will treble - will treble Present conditional - would treble - would treble - would treble - would treble - would treble - would treble Present Perfect - have trebled - have trebled - has trebled - have trebled - have trebled - have trebled Past Perfect - had trebled - had trebled - had trebled - had trebled - had trebled - had trebled Future Perfect - will have trebled - will have trebled - will have trebled - will have trebled - will have trebled - will have trebled Past conditional - would have trebled - would have trebled - would have trebled - would have trebled - would have trebled - would have trebled Imperative - - - treble - - - - - - - -