I can duel you can duel he can duel we can duel you can duel they can duel
V-ing form
I can be dueling you can be dueling he can be dueling we can be dueling you can be dueling they can be dueling
Perfect
I can have dueled you can have dueled he can have dueled we can have dueled you can have dueled they can have dueled
V-ing perfect
I can have been dueling you can have been dueling he can have been dueling we can have been dueling you can have been dueling they can have been dueling
Negation
Simple form
I can't duel you can't duel he can't duel we can't duel you can't duel they can't duel
V-ing form
I can't be dueling you can't be dueling he can't be dueling we can't be dueling you can't be dueling they can't be dueling
Perfect
I can't have dueled you can't have dueled he can't have dueled we can't have dueled you can't have dueled they can't have dueled
V-ing perfect
I can't have been dueling you can't have been dueling he can't have been dueling we can't have been dueling you can't have been dueling they can't have been dueling
Interrogative form
Simple form
can I duel? can you duel? can he duel? can we duel? can you duel? can they duel?
V-ing form
can I be dueling? can you be dueling? can he be dueling? can we be dueling? can you be dueling? can they be dueling?
Perfect
can I have dueled? can you have dueled? can he have dueled? can we have dueled? can you have dueled? can they have dueled?
V-ing perfect
can I have been dueling? can you have been dueling? can he have been dueling? can we have been dueling? can you have been dueling? can they have been dueling?
Interro-negative form
Simple form
can't I duel? can't you duel? can't he duel? can't we duel? can't you duel? can't they duel?
V-ing form
can't I be dueling? can't you be dueling? can't he be dueling? can't we be dueling? can't you be dueling? can't they be dueling?
Perfect
can't I have dueled? can't you have dueled? can't he have dueled? can't we have dueled? can't you have dueled? can't they have dueled?
V-ing perfect
can't I have been dueling? can't you have been dueling? can't he have been dueling? can't we have been dueling? can't you have been dueling? can't they have been dueling?