could stop
Regular verb: stop - stopped- stopped

Affirmation 	
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I could stop
you could stop
she could stop
we could stop
you could stop
they could stop 	I could be stopping
you could be stopping
she could be stopping
we could be stopping
you could be stopping
they could be stopping	I could have stopped
you could have stopped
she could have stopped
we could have stopped
you could have stopped
they could have stopped	I could have been stopping
you could have been stopping
she could have been stopping
we could have been stopping
you could have been stopping
they could have been stopping	

Negation 	
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I couldn't stop
you couldn't stop
she couldn't stop
we couldn't stop
you couldn't stop
they couldn't stop 	I couldn't be stopping
you couldn't be stopping
she couldn't be stopping
we couldn't be stopping
you couldn't be stopping
they couldn't be stopping	I couldn't have stopped
you couldn't have stopped
she couldn't have stopped
we couldn't have stopped
you couldn't have stopped
they couldn't have stopped	I couldn't have been stopping
you couldn't have been stopping
she couldn't have been stopping
we couldn't have been stopping
you couldn't have been stopping
they couldn't have been stopping	

Interrogative form 	
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could I stop?
could you stop?
could she stop?
could we stop?
could you stop?
could they stop? 	could I be stopping?
could you be stopping?
could she be stopping?
could we be stopping?
could you be stopping?
could they be stopping? 	could I have stopped?
could you have stopped?
could she have stopped?
could we have stopped?
could you have stopped?
could they have stopped? 	could I have been stopping?
could you have been stopping?
could she have been stopping?
could we have been stopping?
could you have been stopping?
could they have been stopping? 	

Interro-negative form 	
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couldn't I stop?
couldn't you stop?
couldn't she stop?
couldn't we stop?
couldn't you stop?
couldn't they stop? 	couldn't I be stopping?
couldn't you be stopping?
couldn't she be stopping?
couldn't we be stopping?
couldn't you be stopping?
couldn't they be stopping? 	couldn't I have stopped?
couldn't you have stopped?
couldn't she have stopped?
couldn't we have stopped?
couldn't you have stopped?
couldn't they have stopped? 	couldn't I have been stopping?
couldn't you have been stopping?
couldn't she have been stopping?
couldn't we have been stopping?
couldn't you have been stopping?
couldn't they have been stopping?