Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could fell fell you could fell fell she could fell fell we could fell fell you could fell fell they could fell fell
V-ing form
I could be fell felling you could be fell felling she could be fell felling we could be fell felling you could be fell felling they could be fell felling
Perfect
I could have fell felled you could have fell felled she could have fell felled we could have fell felled you could have fell felled they could have fell felled
V-ing perfect
I could have been fell felling you could have been fell felling she could have been fell felling we could have been fell felling you could have been fell felling they could have been fell felling
Negation
Simple form
I could not fell fell you could not fell fell she could not fell fell we could not fell fell you could not fell fell they could not fell fell
V-ing form
I could not be fell felling you could not be fell felling she could not be fell felling we could not be fell felling you could not be fell felling they could not be fell felling
Perfect
I could not have fell felled you could not have fell felled she could not have fell felled we could not have fell felled you could not have fell felled they could not have fell felled
V-ing perfect
I could not have been fell felling you could not have been fell felling she could not have been fell felling we could not have been fell felling you could not have been fell felling they could not have been fell felling
Interrogative form
Simple form
could I fell fell? could you fell fell? could she fell fell? could we fell fell? could you fell fell? could they fell fell?
V-ing form
could I be fell felling? could you be fell felling? could she be fell felling? could we be fell felling? could you be fell felling? could they be fell felling?
Perfect
could I have fell felled? could you have fell felled? could she have fell felled? could we have fell felled? could you have fell felled? could they have fell felled?
V-ing perfect
could I have been fell felling? could you have been fell felling? could she have been fell felling? could we have been fell felling? could you have been fell felling? could they have been fell felling?
Interro-negative form
Simple form
could I not fell fell? could you not fell fell? could she not fell fell? could we not fell fell? could you not fell fell? could they not fell fell?
V-ing form
could I not be fell felling? could you not be fell felling? could she not be fell felling? could we not be fell felling? could you not be fell felling? could they not be fell felling?
Perfect
could I not have fell felled? could you not have fell felled? could she not have fell felled? could we not have fell felled? could you not have fell felled? could they not have fell felled?
V-ing perfect
could I not have been fell felling? could you not have been fell felling? could she not have been fell felling? could we not have been fell felling? could you not have been fell felling? could they not have been fell felling?