Present participle; Past participle - intervening - intervened Present - intervene - intervene - intervenes - intervene - intervene - intervene Past - intervened - intervened - intervened - intervened - intervened - intervened Future - will intervene - will intervene - will intervene - will intervene - will intervene - will intervene Present conditional - would intervene - would intervene - would intervene - would intervene - would intervene - would intervene Present Perfect - have intervened - have intervened - has intervened - have intervened - have intervened - have intervened Past Perfect - had intervened - had intervened - had intervened - had intervened - had intervened - had intervened Future Perfect - will have intervened - will have intervened - will have intervened - will have intervened - will have intervened - will have intervened Past conditional - would have intervened - would have intervened - would have intervened - would have intervened - would have intervened - would have intervened Imperative - - - intervene - - - - - - - -