I can turn you can turn he can turn we can turn you can turn they can turn
V-ing form
I can be turning you can be turning he can be turning we can be turning you can be turning they can be turning
Perfect
I can have turned you can have turned he can have turned we can have turned you can have turned they can have turned
V-ing perfect
I can have been turning you can have been turning he can have been turning we can have been turning you can have been turning they can have been turning
Negation
Simple form
I can't turn you can't turn he can't turn we can't turn you can't turn they can't turn
V-ing form
I can't be turning you can't be turning he can't be turning we can't be turning you can't be turning they can't be turning
Perfect
I can't have turned you can't have turned he can't have turned we can't have turned you can't have turned they can't have turned
V-ing perfect
I can't have been turning you can't have been turning he can't have been turning we can't have been turning you can't have been turning they can't have been turning
Interrogative form
Simple form
can I turn? can you turn? can he turn? can we turn? can you turn? can they turn?
V-ing form
can I be turning? can you be turning? can he be turning? can we be turning? can you be turning? can they be turning?
Perfect
can I have turned? can you have turned? can he have turned? can we have turned? can you have turned? can they have turned?
V-ing perfect
can I have been turning? can you have been turning? can he have been turning? can we have been turning? can you have been turning? can they have been turning?
Interro-negative form
Simple form
can't I turn? can't you turn? can't he turn? can't we turn? can't you turn? can't they turn?
V-ing form
can't I be turning? can't you be turning? can't he be turning? can't we be turning? can't you be turning? can't they be turning?
Perfect
can't I have turned? can't you have turned? can't he have turned? can't we have turned? can't you have turned? can't they have turned?
V-ing perfect
can't I have been turning? can't you have been turning? can't he have been turning? can't we have been turning? can't you have been turning? can't they have been turning?