English verb conjugation
COULD CLUSTER

Regular verb: cluster - clustered - clustered

Affirmation

Simple form	V-ing form
I could cluster you could cluster he could cluster we could cluster you could cluster they could cluster	I could be clustering you could be clustering he could be clustering we could be clustering you could be clustering they could be clustering
Perfect	V-ing perfect
I could have clustered you could have clustered he could have clustered we could have clustered you could have clustered they could have clustered	I could have been clustering you could have been clustering he could have been clustering we could have been clustering you could have been clustering they could have been clustering

Negation

Simple form	V-ing form
I could not cluster you could not cluster he could not cluster we could not cluster you could not cluster they could not cluster	I could not be clustering you could not be clustering he could not be clustering we could not be clustering you could not be clustering they could not be clustering
Perfect	V-ing perfect
I could not have clustered you could not have clustered he could not have clustered we could not have clustered you could not have clustered they could not have clustered	I could not have been clustering you could not have been clustering he could not have been clustering we could not have been clustering you could not have been clustering they could not have been clustering

Interrogative form

Simple form	V-ing form
could I cluster? could you cluster? could he cluster? could we cluster? could you cluster? could they cluster?	could I be clustering? could you be clustering? could he be clustering? could we be clustering? could you be clustering? could they be clustering?
Perfect	V-ing perfect
could I have clustered? could you have clustered? could he have clustered? could we have clustered? could you have clustered? could they have clustered?	could I have been clustering? could you have been clustering? could he have been clustering? could we have been clustering? could you have been clustering? could they have been clustering?

Interro-negative form

Simple form	V-ing form
could I not cluster? could you not cluster? could he not cluster? could we not cluster? could you not cluster? could they not cluster?	could I not be clustering? could you not be clustering? could he not be clustering? could we not be clustering? could you not be clustering? could they not be clustering?
Perfect	V-ing perfect
could I not have clustered? could you not have clustered? could he not have clustered? could we not have clustered? could you not have clustered? could they not have clustered?	could I not have been clustering? could you not have been clustering? could he not have been clustering? could we not have been clustering? could you not have been clustering? could they not have been clustering?