could buzz
Regular verb: buzz - buzzed- buzzed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could buzz
you could buzz
she could buzz
we could buzz
you could buzz
they could buzz 	I could be buzzing
you could be buzzing
she could be buzzing
we could be buzzing
you could be buzzing
they could be buzzing	I could have buzzed
you could have buzzed
she could have buzzed
we could have buzzed
you could have buzzed
they could have buzzed	I could have been buzzing
you could have been buzzing
she could have been buzzing
we could have been buzzing
you could have been buzzing
they could have been buzzing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't buzz
you couldn't buzz
she couldn't buzz
we couldn't buzz
you couldn't buzz
they couldn't buzz 	I couldn't be buzzing
you couldn't be buzzing
she couldn't be buzzing
we couldn't be buzzing
you couldn't be buzzing
they couldn't be buzzing	I couldn't have buzzed
you couldn't have buzzed
she couldn't have buzzed
we couldn't have buzzed
you couldn't have buzzed
they couldn't have buzzed	I couldn't have been buzzing
you couldn't have been buzzing
she couldn't have been buzzing
we couldn't have been buzzing
you couldn't have been buzzing
they couldn't have been buzzing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I buzz?
could you buzz?
could she buzz?
could we buzz?
could you buzz?
could they buzz? 	could I be buzzing?
could you be buzzing?
could she be buzzing?
could we be buzzing?
could you be buzzing?
could they be buzzing? 	could I have buzzed?
could you have buzzed?
could she have buzzed?
could we have buzzed?
could you have buzzed?
could they have buzzed? 	could I have been buzzing?
could you have been buzzing?
could she have been buzzing?
could we have been buzzing?
could you have been buzzing?
could they have been buzzing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I buzz?
couldn't you buzz?
couldn't she buzz?
couldn't we buzz?
couldn't you buzz?
couldn't they buzz? 	couldn't I be buzzing?
couldn't you be buzzing?
couldn't she be buzzing?
couldn't we be buzzing?
couldn't you be buzzing?
couldn't they be buzzing? 	couldn't I have buzzed?
couldn't you have buzzed?
couldn't she have buzzed?
couldn't we have buzzed?
couldn't you have buzzed?
couldn't they have buzzed? 	couldn't I have been buzzing?
couldn't you have been buzzing?
couldn't she have been buzzing?
couldn't we have been buzzing?
couldn't you have been buzzing?
couldn't they have been buzzing?