could scratch
Regular verb: scratch - scratched- scratched

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could scratch
you could scratch
she could scratch
we could scratch
you could scratch
they could scratch 	I could be scratching
you could be scratching
she could be scratching
we could be scratching
you could be scratching
they could be scratching	I could have scratched
you could have scratched
she could have scratched
we could have scratched
you could have scratched
they could have scratched	I could have been scratching
you could have been scratching
she could have been scratching
we could have been scratching
you could have been scratching
they could have been scratching	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't scratch
you couldn't scratch
she couldn't scratch
we couldn't scratch
you couldn't scratch
they couldn't scratch 	I couldn't be scratching
you couldn't be scratching
she couldn't be scratching
we couldn't be scratching
you couldn't be scratching
they couldn't be scratching	I couldn't have scratched
you couldn't have scratched
she couldn't have scratched
we couldn't have scratched
you couldn't have scratched
they couldn't have scratched	I couldn't have been scratching
you couldn't have been scratching
she couldn't have been scratching
we couldn't have been scratching
you couldn't have been scratching
they couldn't have been scratching	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I scratch?
could you scratch?
could she scratch?
could we scratch?
could you scratch?
could they scratch? 	could I be scratching?
could you be scratching?
could she be scratching?
could we be scratching?
could you be scratching?
could they be scratching? 	could I have scratched?
could you have scratched?
could she have scratched?
could we have scratched?
could you have scratched?
could they have scratched? 	could I have been scratching?
could you have been scratching?
could she have been scratching?
could we have been scratching?
could you have been scratching?
could they have been scratching? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I scratch?
couldn't you scratch?
couldn't she scratch?
couldn't we scratch?
couldn't you scratch?
couldn't they scratch? 	couldn't I be scratching?
couldn't you be scratching?
couldn't she be scratching?
couldn't we be scratching?
couldn't you be scratching?
couldn't they be scratching? 	couldn't I have scratched?
couldn't you have scratched?
couldn't she have scratched?
couldn't we have scratched?
couldn't you have scratched?
couldn't they have scratched? 	couldn't I have been scratching?
couldn't you have been scratching?
couldn't she have been scratching?
couldn't we have been scratching?
couldn't you have been scratching?
couldn't they have been scratching?