could thin
Regular verb: thin - thinned- thinned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could thin
you could thin
she could thin
we could thin
you could thin
they could thin 	I could be thinning
you could be thinning
she could be thinning
we could be thinning
you could be thinning
they could be thinning	I could have thinned
you could have thinned
she could have thinned
we could have thinned
you could have thinned
they could have thinned	I could have been thinning
you could have been thinning
she could have been thinning
we could have been thinning
you could have been thinning
they could have been thinning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't thin
you couldn't thin
she couldn't thin
we couldn't thin
you couldn't thin
they couldn't thin 	I couldn't be thinning
you couldn't be thinning
she couldn't be thinning
we couldn't be thinning
you couldn't be thinning
they couldn't be thinning	I couldn't have thinned
you couldn't have thinned
she couldn't have thinned
we couldn't have thinned
you couldn't have thinned
they couldn't have thinned	I couldn't have been thinning
you couldn't have been thinning
she couldn't have been thinning
we couldn't have been thinning
you couldn't have been thinning
they couldn't have been thinning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I thin?
could you thin?
could she thin?
could we thin?
could you thin?
could they thin? 	could I be thinning?
could you be thinning?
could she be thinning?
could we be thinning?
could you be thinning?
could they be thinning? 	could I have thinned?
could you have thinned?
could she have thinned?
could we have thinned?
could you have thinned?
could they have thinned? 	could I have been thinning?
could you have been thinning?
could she have been thinning?
could we have been thinning?
could you have been thinning?
could they have been thinning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I thin?
couldn't you thin?
couldn't she thin?
couldn't we thin?
couldn't you thin?
couldn't they thin? 	couldn't I be thinning?
couldn't you be thinning?
couldn't she be thinning?
couldn't we be thinning?
couldn't you be thinning?
couldn't they be thinning? 	couldn't I have thinned?
couldn't you have thinned?
couldn't she have thinned?
couldn't we have thinned?
couldn't you have thinned?
couldn't they have thinned? 	couldn't I have been thinning?
couldn't you have been thinning?
couldn't she have been thinning?
couldn't we have been thinning?
couldn't you have been thinning?
couldn't they have been thinning?