could winnow
Regular verb: winnow - winnowed- winnowed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could winnow
you could winnow
he could winnow
we could winnow
you could winnow
they could winnow 	I could be winnowing
you could be winnowing
he could be winnowing
we could be winnowing
you could be winnowing
they could be winnowing	I could have winnowed
you could have winnowed
he could have winnowed
we could have winnowed
you could have winnowed
they could have winnowed	I could have been winnowing
you could have been winnowing
he could have been winnowing
we could have been winnowing
you could have been winnowing
they could have been winnowing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't winnow
you couldn't winnow
he couldn't winnow
we couldn't winnow
you couldn't winnow
they couldn't winnow 	I couldn't be winnowing
you couldn't be winnowing
he couldn't be winnowing
we couldn't be winnowing
you couldn't be winnowing
they couldn't be winnowing	I couldn't have winnowed
you couldn't have winnowed
he couldn't have winnowed
we couldn't have winnowed
you couldn't have winnowed
they couldn't have winnowed	I couldn't have been winnowing
you couldn't have been winnowing
he couldn't have been winnowing
we couldn't have been winnowing
you couldn't have been winnowing
they couldn't have been winnowing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I winnow?
could you winnow?
could he winnow?
could we winnow?
could you winnow?
could they winnow? 	could I be winnowing?
could you be winnowing?
could he be winnowing?
could we be winnowing?
could you be winnowing?
could they be winnowing? 	could I have winnowed?
could you have winnowed?
could he have winnowed?
could we have winnowed?
could you have winnowed?
could they have winnowed? 	could I have been winnowing?
could you have been winnowing?
could he have been winnowing?
could we have been winnowing?
could you have been winnowing?
could they have been winnowing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I winnow?
couldn't you winnow?
couldn't he winnow?
couldn't we winnow?
couldn't you winnow?
couldn't they winnow? 	couldn't I be winnowing?
couldn't you be winnowing?
couldn't he be winnowing?
couldn't we be winnowing?
couldn't you be winnowing?
couldn't they be winnowing? 	couldn't I have winnowed?
couldn't you have winnowed?
couldn't he have winnowed?
couldn't we have winnowed?
couldn't you have winnowed?
couldn't they have winnowed? 	couldn't I have been winnowing?
couldn't you have been winnowing?
couldn't he have been winnowing?
couldn't we have been winnowing?
couldn't you have been winnowing?
couldn't they have been winnowing?