I can upgrade you can upgrade he can upgrade we can upgrade you can upgrade they can upgrade
V-ing form
I can be upgrading you can be upgrading he can be upgrading we can be upgrading you can be upgrading they can be upgrading
Perfect
I can have upgraded you can have upgraded he can have upgraded we can have upgraded you can have upgraded they can have upgraded
V-ing perfect
I can have been upgrading you can have been upgrading he can have been upgrading we can have been upgrading you can have been upgrading they can have been upgrading
Negation
Simple form
I can't upgrade you can't upgrade he can't upgrade we can't upgrade you can't upgrade they can't upgrade
V-ing form
I can't be upgrading you can't be upgrading he can't be upgrading we can't be upgrading you can't be upgrading they can't be upgrading
Perfect
I can't have upgraded you can't have upgraded he can't have upgraded we can't have upgraded you can't have upgraded they can't have upgraded
V-ing perfect
I can't have been upgrading you can't have been upgrading he can't have been upgrading we can't have been upgrading you can't have been upgrading they can't have been upgrading
Interrogative form
Simple form
can I upgrade? can you upgrade? can he upgrade? can we upgrade? can you upgrade? can they upgrade?
V-ing form
can I be upgrading? can you be upgrading? can he be upgrading? can we be upgrading? can you be upgrading? can they be upgrading?
Perfect
can I have upgraded? can you have upgraded? can he have upgraded? can we have upgraded? can you have upgraded? can they have upgraded?
V-ing perfect
can I have been upgrading? can you have been upgrading? can he have been upgrading? can we have been upgrading? can you have been upgrading? can they have been upgrading?
Interro-negative form
Simple form
can't I upgrade? can't you upgrade? can't he upgrade? can't we upgrade? can't you upgrade? can't they upgrade?
V-ing form
can't I be upgrading? can't you be upgrading? can't he be upgrading? can't we be upgrading? can't you be upgrading? can't they be upgrading?
Perfect
can't I have upgraded? can't you have upgraded? can't he have upgraded? can't we have upgraded? can't you have upgraded? can't they have upgraded?
V-ing perfect
can't I have been upgrading? can't you have been upgrading? can't he have been upgrading? can't we have been upgrading? can't you have been upgrading? can't they have been upgrading?