could upgrade
Regular verb: upgrade - upgraded- upgraded

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could upgrade
you could upgrade
she could upgrade
we could upgrade
you could upgrade
they could upgrade 	I could be upgrading
you could be upgrading
she could be upgrading
we could be upgrading
you could be upgrading
they could be upgrading	I could have upgraded
you could have upgraded
she could have upgraded
we could have upgraded
you could have upgraded
they could have upgraded	I could have been upgrading
you could have been upgrading
she could have been upgrading
we could have been upgrading
you could have been upgrading
they could have been upgrading	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't upgrade
you couldn't upgrade
she couldn't upgrade
we couldn't upgrade
you couldn't upgrade
they couldn't upgrade 	I couldn't be upgrading
you couldn't be upgrading
she couldn't be upgrading
we couldn't be upgrading
you couldn't be upgrading
they couldn't be upgrading	I couldn't have upgraded
you couldn't have upgraded
she couldn't have upgraded
we couldn't have upgraded
you couldn't have upgraded
they couldn't have upgraded	I couldn't have been upgrading
you couldn't have been upgrading
she couldn't have been upgrading
we couldn't have been upgrading
you couldn't have been upgrading
they couldn't have been upgrading	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I upgrade?
could you upgrade?
could she upgrade?
could we upgrade?
could you upgrade?
could they upgrade? 	could I be upgrading?
could you be upgrading?
could she be upgrading?
could we be upgrading?
could you be upgrading?
could they be upgrading? 	could I have upgraded?
could you have upgraded?
could she have upgraded?
could we have upgraded?
could you have upgraded?
could they have upgraded? 	could I have been upgrading?
could you have been upgrading?
could she have been upgrading?
could we have been upgrading?
could you have been upgrading?
could they have been upgrading? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I upgrade?
couldn't you upgrade?
couldn't she upgrade?
couldn't we upgrade?
couldn't you upgrade?
couldn't they upgrade? 	couldn't I be upgrading?
couldn't you be upgrading?
couldn't she be upgrading?
couldn't we be upgrading?
couldn't you be upgrading?
couldn't they be upgrading? 	couldn't I have upgraded?
couldn't you have upgraded?
couldn't she have upgraded?
couldn't we have upgraded?
couldn't you have upgraded?
couldn't they have upgraded? 	couldn't I have been upgrading?
couldn't you have been upgrading?
couldn't she have been upgrading?
couldn't we have been upgrading?
couldn't you have been upgrading?
couldn't they have been upgrading?