could lesson
Regular verb: lesson - lessoned- lessoned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could lesson
you could lesson
he could lesson
we could lesson
you could lesson
they could lesson 	I could be lessoning
you could be lessoning
he could be lessoning
we could be lessoning
you could be lessoning
they could be lessoning	I could have lessoned
you could have lessoned
he could have lessoned
we could have lessoned
you could have lessoned
they could have lessoned	I could have been lessoning
you could have been lessoning
he could have been lessoning
we could have been lessoning
you could have been lessoning
they could have been lessoning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't lesson
you couldn't lesson
he couldn't lesson
we couldn't lesson
you couldn't lesson
they couldn't lesson 	I couldn't be lessoning
you couldn't be lessoning
he couldn't be lessoning
we couldn't be lessoning
you couldn't be lessoning
they couldn't be lessoning	I couldn't have lessoned
you couldn't have lessoned
he couldn't have lessoned
we couldn't have lessoned
you couldn't have lessoned
they couldn't have lessoned	I couldn't have been lessoning
you couldn't have been lessoning
he couldn't have been lessoning
we couldn't have been lessoning
you couldn't have been lessoning
they couldn't have been lessoning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I lesson?
could you lesson?
could he lesson?
could we lesson?
could you lesson?
could they lesson? 	could I be lessoning?
could you be lessoning?
could he be lessoning?
could we be lessoning?
could you be lessoning?
could they be lessoning? 	could I have lessoned?
could you have lessoned?
could he have lessoned?
could we have lessoned?
could you have lessoned?
could they have lessoned? 	could I have been lessoning?
could you have been lessoning?
could he have been lessoning?
could we have been lessoning?
could you have been lessoning?
could they have been lessoning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I lesson?
couldn't you lesson?
couldn't he lesson?
couldn't we lesson?
couldn't you lesson?
couldn't they lesson? 	couldn't I be lessoning?
couldn't you be lessoning?
couldn't he be lessoning?
couldn't we be lessoning?
couldn't you be lessoning?
couldn't they be lessoning? 	couldn't I have lessoned?
couldn't you have lessoned?
couldn't he have lessoned?
couldn't we have lessoned?
couldn't you have lessoned?
couldn't they have lessoned? 	couldn't I have been lessoning?
couldn't you have been lessoning?
couldn't he have been lessoning?
couldn't we have been lessoning?
couldn't you have been lessoning?
couldn't they have been lessoning?