I can frog you can frog he can frog we can frog you can frog they can frog
V-ing form
I can be froging you can be froging he can be froging we can be froging you can be froging they can be froging
Perfect
I can have froged you can have froged he can have froged we can have froged you can have froged they can have froged
V-ing perfect
I can have been froging you can have been froging he can have been froging we can have been froging you can have been froging they can have been froging
Negation
Simple form
I can't frog you can't frog he can't frog we can't frog you can't frog they can't frog
V-ing form
I can't be froging you can't be froging he can't be froging we can't be froging you can't be froging they can't be froging
Perfect
I can't have froged you can't have froged he can't have froged we can't have froged you can't have froged they can't have froged
V-ing perfect
I can't have been froging you can't have been froging he can't have been froging we can't have been froging you can't have been froging they can't have been froging
Interrogative form
Simple form
can I frog? can you frog? can he frog? can we frog? can you frog? can they frog?
V-ing form
can I be froging? can you be froging? can he be froging? can we be froging? can you be froging? can they be froging?
Perfect
can I have froged? can you have froged? can he have froged? can we have froged? can you have froged? can they have froged?
V-ing perfect
can I have been froging? can you have been froging? can he have been froging? can we have been froging? can you have been froging? can they have been froging?
Interro-negative form
Simple form
can't I frog? can't you frog? can't he frog? can't we frog? can't you frog? can't they frog?
V-ing form
can't I be froging? can't you be froging? can't he be froging? can't we be froging? can't you be froging? can't they be froging?
Perfect
can't I have froged? can't you have froged? can't he have froged? can't we have froged? can't you have froged? can't they have froged?
V-ing perfect
can't I have been froging? can't you have been froging? can't he have been froging? can't we have been froging? can't you have been froging? can't they have been froging?