English verb conjugation
COULD TREPAN

Regular verb: trepan - trepanned - trepanned

Affirmation

Simple form	V-ing form
I could trepan you could trepan he could trepan we could trepan you could trepan they could trepan	I could be trepanning you could be trepanning he could be trepanning we could be trepanning you could be trepanning they could be trepanning
Perfect	V-ing perfect
I could have trepanned you could have trepanned he could have trepanned we could have trepanned you could have trepanned they could have trepanned	I could have been trepanning you could have been trepanning he could have been trepanning we could have been trepanning you could have been trepanning they could have been trepanning

Negation

Simple form	V-ing form
I could not trepan you could not trepan he could not trepan we could not trepan you could not trepan they could not trepan	I could not be trepanning you could not be trepanning he could not be trepanning we could not be trepanning you could not be trepanning they could not be trepanning
Perfect	V-ing perfect
I could not have trepanned you could not have trepanned he could not have trepanned we could not have trepanned you could not have trepanned they could not have trepanned	I could not have been trepanning you could not have been trepanning he could not have been trepanning we could not have been trepanning you could not have been trepanning they could not have been trepanning

Interrogative form

Simple form	V-ing form
could I trepan? could you trepan? could he trepan? could we trepan? could you trepan? could they trepan?	could I be trepanning? could you be trepanning? could he be trepanning? could we be trepanning? could you be trepanning? could they be trepanning?
Perfect	V-ing perfect
could I have trepanned? could you have trepanned? could he have trepanned? could we have trepanned? could you have trepanned? could they have trepanned?	could I have been trepanning? could you have been trepanning? could he have been trepanning? could we have been trepanning? could you have been trepanning? could they have been trepanning?

Interro-negative form

Simple form	V-ing form
could I not trepan? could you not trepan? could he not trepan? could we not trepan? could you not trepan? could they not trepan?	could I not be trepanning? could you not be trepanning? could he not be trepanning? could we not be trepanning? could you not be trepanning? could they not be trepanning?
Perfect	V-ing perfect
could I not have trepanned? could you not have trepanned? could he not have trepanned? could we not have trepanned? could you not have trepanned? could they not have trepanned?	could I not have been trepanning? could you not have been trepanning? could he not have been trepanning? could we not have been trepanning? could you not have been trepanning? could they not have been trepanning?