I can hammer you can hammer she can hammer we can hammer you can hammer they can hammer
V-ing form
I can be hammering you can be hammering she can be hammering we can be hammering you can be hammering they can be hammering
Perfect
I can have hammered you can have hammered she 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 she 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 she 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 she 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 she 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 she 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 she hammer? can we hammer? can you hammer? can they hammer?
V-ing form
can I be hammering? can you be hammering? can she be hammering? can we be hammering? can you be hammering? can they be hammering?
Perfect
can I have hammered? can you have hammered? can she 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 she 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 she 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 she 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 she 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 she have been hammering? can't we have been hammering? can't you have been hammering? can't they have been hammering?