I can fever you can fever he can fever we can fever you can fever they can fever
V-ing form
I can be fevering you can be fevering he can be fevering we can be fevering you can be fevering they can be fevering
Perfect
I can have fevered you can have fevered he can have fevered we can have fevered you can have fevered they can have fevered
V-ing perfect
I can have been fevering you can have been fevering he can have been fevering we can have been fevering you can have been fevering they can have been fevering
Negation
Simple form
I can't fever you can't fever he can't fever we can't fever you can't fever they can't fever
V-ing form
I can't be fevering you can't be fevering he can't be fevering we can't be fevering you can't be fevering they can't be fevering
Perfect
I can't have fevered you can't have fevered he can't have fevered we can't have fevered you can't have fevered they can't have fevered
V-ing perfect
I can't have been fevering you can't have been fevering he can't have been fevering we can't have been fevering you can't have been fevering they can't have been fevering
Interrogative form
Simple form
can I fever? can you fever? can he fever? can we fever? can you fever? can they fever?
V-ing form
can I be fevering? can you be fevering? can he be fevering? can we be fevering? can you be fevering? can they be fevering?
Perfect
can I have fevered? can you have fevered? can he have fevered? can we have fevered? can you have fevered? can they have fevered?
V-ing perfect
can I have been fevering? can you have been fevering? can he have been fevering? can we have been fevering? can you have been fevering? can they have been fevering?
Interro-negative form
Simple form
can't I fever? can't you fever? can't he fever? can't we fever? can't you fever? can't they fever?
V-ing form
can't I be fevering? can't you be fevering? can't he be fevering? can't we be fevering? can't you be fevering? can't they be fevering?
Perfect
can't I have fevered? can't you have fevered? can't he have fevered? can't we have fevered? can't you have fevered? can't they have fevered?
V-ing perfect
can't I have been fevering? can't you have been fevering? can't he have been fevering? can't we have been fevering? can't you have been fevering? can't they have been fevering?