could knell
Regular verb: knell - knelled- knelled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could knell
you could knell
he could knell
we could knell
you could knell
they could knell 	I could be knelling
you could be knelling
he could be knelling
we could be knelling
you could be knelling
they could be knelling	I could have knelled
you could have knelled
he could have knelled
we could have knelled
you could have knelled
they could have knelled	I could have been knelling
you could have been knelling
he could have been knelling
we could have been knelling
you could have been knelling
they could have been knelling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not knell
you could not knell
he could not knell
we could not knell
you could not knell
they could not knell 	I could not be knelling
you could not be knelling
he could not be knelling
we could not be knelling
you could not be knelling
they could not be knelling	I could not have knelled
you could not have knelled
he could not have knelled
we could not have knelled
you could not have knelled
they could not have knelled	I could not have been knelling
you could not have been knelling
he could not have been knelling
we could not have been knelling
you could not have been knelling
they could not have been knelling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I knell?
could you knell?
could he knell?
could we knell?
could you knell?
could they knell? 	could I be knelling?
could you be knelling?
could he be knelling?
could we be knelling?
could you be knelling?
could they be knelling? 	could I have knelled?
could you have knelled?
could he have knelled?
could we have knelled?
could you have knelled?
could they have knelled? 	could I have been knelling?
could you have been knelling?
could he have been knelling?
could we have been knelling?
could you have been knelling?
could they have been knelling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not knell?
could you not knell?
could he not knell?
could we not knell?
could you not knell?
could they not knell? 	could I not be knelling?
could you not be knelling?
could he not be knelling?
could we not be knelling?
could you not be knelling?
could they not be knelling? 	could I not have knelled?
could you not have knelled?
could he not have knelled?
could we not have knelled?
could you not have knelled?
could they not have knelled? 	could I not have been knelling?
could you not have been knelling?
could he not have been knelling?
could we not have been knelling?
could you not have been knelling?
could they not have been knelling?