Present participle; Past participle - littering - littered Present - litter - litter - litters - litter - litter - litter Past - littered - littered - littered - littered - littered - littered Future - will litter - will litter - will litter - will litter - will litter - will litter Present conditional - would litter - would litter - would litter - would litter - would litter - would litter Present Perfect - have littered - have littered - has littered - have littered - have littered - have littered Past Perfect - had littered - had littered - had littered - had littered - had littered - had littered Future Perfect - will have littered - will have littered - will have littered - will have littered - will have littered - will have littered Past conditional - would have littered - would have littered - would have littered - would have littered - would have littered - would have littered Imperative - - - litter - - - - - - - -