could stool
Regular verb: stool - stooled- stooled

Affirmation 	
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I could stool
you could stool
he could stool
we could stool
you could stool
they could stool 	I could be stooling
you could be stooling
he could be stooling
we could be stooling
you could be stooling
they could be stooling	I could have stooled
you could have stooled
he could have stooled
we could have stooled
you could have stooled
they could have stooled	I could have been stooling
you could have been stooling
he could have been stooling
we could have been stooling
you could have been stooling
they could have been stooling	

Negation 	
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I couldn't stool
you couldn't stool
he couldn't stool
we couldn't stool
you couldn't stool
they couldn't stool 	I couldn't be stooling
you couldn't be stooling
he couldn't be stooling
we couldn't be stooling
you couldn't be stooling
they couldn't be stooling	I couldn't have stooled
you couldn't have stooled
he couldn't have stooled
we couldn't have stooled
you couldn't have stooled
they couldn't have stooled	I couldn't have been stooling
you couldn't have been stooling
he couldn't have been stooling
we couldn't have been stooling
you couldn't have been stooling
they couldn't have been stooling	

Interrogative form 	
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could I stool?
could you stool?
could he stool?
could we stool?
could you stool?
could they stool? 	could I be stooling?
could you be stooling?
could he be stooling?
could we be stooling?
could you be stooling?
could they be stooling? 	could I have stooled?
could you have stooled?
could he have stooled?
could we have stooled?
could you have stooled?
could they have stooled? 	could I have been stooling?
could you have been stooling?
could he have been stooling?
could we have been stooling?
could you have been stooling?
could they have been stooling? 	

Interro-negative form 	
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couldn't I stool?
couldn't you stool?
couldn't he stool?
couldn't we stool?
couldn't you stool?
couldn't they stool? 	couldn't I be stooling?
couldn't you be stooling?
couldn't he be stooling?
couldn't we be stooling?
couldn't you be stooling?
couldn't they be stooling? 	couldn't I have stooled?
couldn't you have stooled?
couldn't he have stooled?
couldn't we have stooled?
couldn't you have stooled?
couldn't they have stooled? 	couldn't I have been stooling?
couldn't you have been stooling?
couldn't he have been stooling?
couldn't we have been stooling?
couldn't you have been stooling?
couldn't they have been stooling?