Present participle; Past participle - contributing - contributed Present - contribute - contribute - contributes - contribute - contribute - contribute Past - contributed - contributed - contributed - contributed - contributed - contributed Future - will contribute - will contribute - will contribute - will contribute - will contribute - will contribute Present conditional - would contribute - would contribute - would contribute - would contribute - would contribute - would contribute Present Perfect - have contributed - have contributed - has contributed - have contributed - have contributed - have contributed Past Perfect - had contributed - had contributed - had contributed - had contributed - had contributed - had contributed Future Perfect - will have contributed - will have contributed - will have contributed - will have contributed - will have contributed - will have contributed Past conditional - would have contributed - would have contributed - would have contributed - would have contributed - would have contributed - would have contributed Imperative - - - contribute - - - - - - - -