Present participle; Past participle - clustering - clustered Present - cluster - cluster - clusters - cluster - cluster - cluster Past - clustered - clustered - clustered - clustered - clustered - clustered Future - will cluster - will cluster - will cluster - will cluster - will cluster - will cluster Present conditional - would cluster - would cluster - would cluster - would cluster - would cluster - would cluster Present Perfect - have clustered - have clustered - has clustered - have clustered - have clustered - have clustered Past Perfect - had clustered - had clustered - had clustered - had clustered - had clustered - had clustered Future Perfect - will have clustered - will have clustered - will have clustered - will have clustered - will have clustered - will have clustered Past conditional - would have clustered - would have clustered - would have clustered - would have clustered - would have clustered - would have clustered Imperative - - - cluster - - - - - - - -