I can head you can head he can head we can head you can head they can head
V-ing form
I can be heading you can be heading he can be heading we can be heading you can be heading they can be heading
Perfect
I can have headed you can have headed he can have headed we can have headed you can have headed they can have headed
V-ing perfect
I can have been heading you can have been heading he can have been heading we can have been heading you can have been heading they can have been heading
Negation
Simple form
I can't head you can't head he can't head we can't head you can't head they can't head
V-ing form
I can't be heading you can't be heading he can't be heading we can't be heading you can't be heading they can't be heading
Perfect
I can't have headed you can't have headed he can't have headed we can't have headed you can't have headed they can't have headed
V-ing perfect
I can't have been heading you can't have been heading he can't have been heading we can't have been heading you can't have been heading they can't have been heading
Interrogative form
Simple form
can I head? can you head? can he head? can we head? can you head? can they head?
V-ing form
can I be heading? can you be heading? can he be heading? can we be heading? can you be heading? can they be heading?
Perfect
can I have headed? can you have headed? can he have headed? can we have headed? can you have headed? can they have headed?
V-ing perfect
can I have been heading? can you have been heading? can he have been heading? can we have been heading? can you have been heading? can they have been heading?
Interro-negative form
Simple form
can't I head? can't you head? can't he head? can't we head? can't you head? can't they head?
V-ing form
can't I be heading? can't you be heading? can't he be heading? can't we be heading? can't you be heading? can't they be heading?
Perfect
can't I have headed? can't you have headed? can't he have headed? can't we have headed? can't you have headed? can't they have headed?
V-ing perfect
can't I have been heading? can't you have been heading? can't he have been heading? can't we have been heading? can't you have been heading? can't they have been heading?