I can perk you can perk he can perk we can perk you can perk they can perk
V-ing form
I can be perking you can be perking he can be perking we can be perking you can be perking they can be perking
Perfect
I can have perked you can have perked he can have perked we can have perked you can have perked they can have perked
V-ing perfect
I can have been perking you can have been perking he can have been perking we can have been perking you can have been perking they can have been perking
Negation
Simple form
I can't perk you can't perk he can't perk we can't perk you can't perk they can't perk
V-ing form
I can't be perking you can't be perking he can't be perking we can't be perking you can't be perking they can't be perking
Perfect
I can't have perked you can't have perked he can't have perked we can't have perked you can't have perked they can't have perked
V-ing perfect
I can't have been perking you can't have been perking he can't have been perking we can't have been perking you can't have been perking they can't have been perking
Interrogative form
Simple form
can I perk? can you perk? can he perk? can we perk? can you perk? can they perk?
V-ing form
can I be perking? can you be perking? can he be perking? can we be perking? can you be perking? can they be perking?
Perfect
can I have perked? can you have perked? can he have perked? can we have perked? can you have perked? can they have perked?
V-ing perfect
can I have been perking? can you have been perking? can he have been perking? can we have been perking? can you have been perking? can they have been perking?
Interro-negative form
Simple form
can't I perk? can't you perk? can't he perk? can't we perk? can't you perk? can't they perk?
V-ing form
can't I be perking? can't you be perking? can't he be perking? can't we be perking? can't you be perking? can't they be perking?
Perfect
can't I have perked? can't you have perked? can't he have perked? can't we have perked? can't you have perked? can't they have perked?
V-ing perfect
can't I have been perking? can't you have been perking? can't he have been perking? can't we have been perking? can't you have been perking? can't they have been perking?