Present participle; Past participle - doubting - doubted Present - doubt - doubt - doubts - doubt - doubt - doubt Past - doubted - doubted - doubted - doubted - doubted - doubted Future - will doubt - will doubt - will doubt - will doubt - will doubt - will doubt Present conditional - would doubt - would doubt - would doubt - would doubt - would doubt - would doubt Present Perfect - have doubted - have doubted - has doubted - have doubted - have doubted - have doubted Past Perfect - had doubted - had doubted - had doubted - had doubted - had doubted - had doubted Future Perfect - will have doubted - will have doubted - will have doubted - will have doubted - will have doubted - will have doubted Past conditional - would have doubted - would have doubted - would have doubted - would have doubted - would have doubted - would have doubted Imperative - - - doubt - - - - - - - -