I can joke you can joke he can joke we can joke you can joke they can joke
V-ing form
I can be joking you can be joking he can be joking we can be joking you can be joking they can be joking
Perfect
I can have joked you can have joked he can have joked we can have joked you can have joked they can have joked
V-ing perfect
I can have been joking you can have been joking he can have been joking we can have been joking you can have been joking they can have been joking
Negation
Simple form
I can't joke you can't joke he can't joke we can't joke you can't joke they can't joke
V-ing form
I can't be joking you can't be joking he can't be joking we can't be joking you can't be joking they can't be joking
Perfect
I can't have joked you can't have joked he can't have joked we can't have joked you can't have joked they can't have joked
V-ing perfect
I can't have been joking you can't have been joking he can't have been joking we can't have been joking you can't have been joking they can't have been joking
Interrogative form
Simple form
can I joke? can you joke? can he joke? can we joke? can you joke? can they joke?
V-ing form
can I be joking? can you be joking? can he be joking? can we be joking? can you be joking? can they be joking?
Perfect
can I have joked? can you have joked? can he have joked? can we have joked? can you have joked? can they have joked?
V-ing perfect
can I have been joking? can you have been joking? can he have been joking? can we have been joking? can you have been joking? can they have been joking?
Interro-negative form
Simple form
can't I joke? can't you joke? can't he joke? can't we joke? can't you joke? can't they joke?
V-ing form
can't I be joking? can't you be joking? can't he be joking? can't we be joking? can't you be joking? can't they be joking?
Perfect
can't I have joked? can't you have joked? can't he have joked? can't we have joked? can't you have joked? can't they have joked?
V-ing perfect
can't I have been joking? can't you have been joking? can't he have been joking? can't we have been joking? can't you have been joking? can't they have been joking?