could strum
Regular verb: strum - strummed- strummed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could strum
you could strum
she could strum
we could strum
you could strum
they could strum 	I could be strumming
you could be strumming
she could be strumming
we could be strumming
you could be strumming
they could be strumming	I could have strummed
you could have strummed
she could have strummed
we could have strummed
you could have strummed
they could have strummed	I could have been strumming
you could have been strumming
she could have been strumming
we could have been strumming
you could have been strumming
they could have been strumming	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't strum
you couldn't strum
she couldn't strum
we couldn't strum
you couldn't strum
they couldn't strum 	I couldn't be strumming
you couldn't be strumming
she couldn't be strumming
we couldn't be strumming
you couldn't be strumming
they couldn't be strumming	I couldn't have strummed
you couldn't have strummed
she couldn't have strummed
we couldn't have strummed
you couldn't have strummed
they couldn't have strummed	I couldn't have been strumming
you couldn't have been strumming
she couldn't have been strumming
we couldn't have been strumming
you couldn't have been strumming
they couldn't have been strumming	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I strum?
could you strum?
could she strum?
could we strum?
could you strum?
could they strum? 	could I be strumming?
could you be strumming?
could she be strumming?
could we be strumming?
could you be strumming?
could they be strumming? 	could I have strummed?
could you have strummed?
could she have strummed?
could we have strummed?
could you have strummed?
could they have strummed? 	could I have been strumming?
could you have been strumming?
could she have been strumming?
could we have been strumming?
could you have been strumming?
could they have been strumming? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I strum?
couldn't you strum?
couldn't she strum?
couldn't we strum?
couldn't you strum?
couldn't they strum? 	couldn't I be strumming?
couldn't you be strumming?
couldn't she be strumming?
couldn't we be strumming?
couldn't you be strumming?
couldn't they be strumming? 	couldn't I have strummed?
couldn't you have strummed?
couldn't she have strummed?
couldn't we have strummed?
couldn't you have strummed?
couldn't they have strummed? 	couldn't I have been strumming?
couldn't you have been strumming?
couldn't she have been strumming?
couldn't we have been strumming?
couldn't you have been strumming?
couldn't they have been strumming?