could cough
Regular verb: cough - coughed- coughed

Affirmation 	
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I could cough
you could cough
she could cough
we could cough
you could cough
they could cough 	I could be coughing
you could be coughing
she could be coughing
we could be coughing
you could be coughing
they could be coughing	I could have coughed
you could have coughed
she could have coughed
we could have coughed
you could have coughed
they could have coughed	I could have been coughing
you could have been coughing
she could have been coughing
we could have been coughing
you could have been coughing
they could have been coughing	

Negation 	
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I couldn't cough
you couldn't cough
she couldn't cough
we couldn't cough
you couldn't cough
they couldn't cough 	I couldn't be coughing
you couldn't be coughing
she couldn't be coughing
we couldn't be coughing
you couldn't be coughing
they couldn't be coughing	I couldn't have coughed
you couldn't have coughed
she couldn't have coughed
we couldn't have coughed
you couldn't have coughed
they couldn't have coughed	I couldn't have been coughing
you couldn't have been coughing
she couldn't have been coughing
we couldn't have been coughing
you couldn't have been coughing
they couldn't have been coughing	

Interrogative form 	
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could I cough?
could you cough?
could she cough?
could we cough?
could you cough?
could they cough? 	could I be coughing?
could you be coughing?
could she be coughing?
could we be coughing?
could you be coughing?
could they be coughing? 	could I have coughed?
could you have coughed?
could she have coughed?
could we have coughed?
could you have coughed?
could they have coughed? 	could I have been coughing?
could you have been coughing?
could she have been coughing?
could we have been coughing?
could you have been coughing?
could they have been coughing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I cough?
couldn't you cough?
couldn't she cough?
couldn't we cough?
couldn't you cough?
couldn't they cough? 	couldn't I be coughing?
couldn't you be coughing?
couldn't she be coughing?
couldn't we be coughing?
couldn't you be coughing?
couldn't they be coughing? 	couldn't I have coughed?
couldn't you have coughed?
couldn't she have coughed?
couldn't we have coughed?
couldn't you have coughed?
couldn't they have coughed? 	couldn't I have been coughing?
couldn't you have been coughing?
couldn't she have been coughing?
couldn't we have been coughing?
couldn't you have been coughing?
couldn't they have been coughing?