could bum
Regular verb: bum - bummed- bummed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could bum
you could bum
she could bum
we could bum
you could bum
they could bum 	I could be bumming
you could be bumming
she could be bumming
we could be bumming
you could be bumming
they could be bumming	I could have bummed
you could have bummed
she could have bummed
we could have bummed
you could have bummed
they could have bummed	I could have been bumming
you could have been bumming
she could have been bumming
we could have been bumming
you could have been bumming
they could have been bumming	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't bum
you couldn't bum
she couldn't bum
we couldn't bum
you couldn't bum
they couldn't bum 	I couldn't be bumming
you couldn't be bumming
she couldn't be bumming
we couldn't be bumming
you couldn't be bumming
they couldn't be bumming	I couldn't have bummed
you couldn't have bummed
she couldn't have bummed
we couldn't have bummed
you couldn't have bummed
they couldn't have bummed	I couldn't have been bumming
you couldn't have been bumming
she couldn't have been bumming
we couldn't have been bumming
you couldn't have been bumming
they couldn't have been bumming	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I bum?
could you bum?
could she bum?
could we bum?
could you bum?
could they bum? 	could I be bumming?
could you be bumming?
could she be bumming?
could we be bumming?
could you be bumming?
could they be bumming? 	could I have bummed?
could you have bummed?
could she have bummed?
could we have bummed?
could you have bummed?
could they have bummed? 	could I have been bumming?
could you have been bumming?
could she have been bumming?
could we have been bumming?
could you have been bumming?
could they have been bumming? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I bum?
couldn't you bum?
couldn't she bum?
couldn't we bum?
couldn't you bum?
couldn't they bum? 	couldn't I be bumming?
couldn't you be bumming?
couldn't she be bumming?
couldn't we be bumming?
couldn't you be bumming?
couldn't they be bumming? 	couldn't I have bummed?
couldn't you have bummed?
couldn't she have bummed?
couldn't we have bummed?
couldn't you have bummed?
couldn't they have bummed? 	couldn't I have been bumming?
couldn't you have been bumming?
couldn't she have been bumming?
couldn't we have been bumming?
couldn't you have been bumming?
couldn't they have been bumming?