I can hammer you can hammer he can hammer we can hammer you can hammer they can hammer
V-ing form
I can be hammering you can be hammering he can be hammering we can be hammering you can be hammering they can be hammering
Perfect
I can have hammered you can have hammered he can have hammered we can have hammered you can have hammered they can have hammered
V-ing perfect
I can have been hammering you can have been hammering he can have been hammering we can have been hammering you can have been hammering they can have been hammering
Negation
Simple form
I can't hammer you can't hammer he can't hammer we can't hammer you can't hammer they can't hammer
V-ing form
I can't be hammering you can't be hammering he can't be hammering we can't be hammering you can't be hammering they can't be hammering
Perfect
I can't have hammered you can't have hammered he can't have hammered we can't have hammered you can't have hammered they can't have hammered
V-ing perfect
I can't have been hammering you can't have been hammering he can't have been hammering we can't have been hammering you can't have been hammering they can't have been hammering
Interrogative form
Simple form
can I hammer? can you hammer? can he hammer? can we hammer? can you hammer? can they hammer?
V-ing form
can I be hammering? can you be hammering? can he be hammering? can we be hammering? can you be hammering? can they be hammering?
Perfect
can I have hammered? can you have hammered? can he have hammered? can we have hammered? can you have hammered? can they have hammered?
V-ing perfect
can I have been hammering? can you have been hammering? can he have been hammering? can we have been hammering? can you have been hammering? can they have been hammering?
Interro-negative form
Simple form
can't I hammer? can't you hammer? can't he hammer? can't we hammer? can't you hammer? can't they hammer?
V-ing form
can't I be hammering? can't you be hammering? can't he be hammering? can't we be hammering? can't you be hammering? can't they be hammering?
Perfect
can't I have hammered? can't you have hammered? can't he have hammered? can't we have hammered? can't you have hammered? can't they have hammered?
V-ing perfect
can't I have been hammering? can't you have been hammering? can't he have been hammering? can't we have been hammering? can't you have been hammering? can't they have been hammering?