I can treat you can treat he can treat we can treat you can treat they can treat
V-ing form
I can be treating you can be treating he can be treating we can be treating you can be treating they can be treating
Perfect
I can have treated you can have treated he can have treated we can have treated you can have treated they can have treated
V-ing perfect
I can have been treating you can have been treating he can have been treating we can have been treating you can have been treating they can have been treating
Negation
Simple form
I can't treat you can't treat he can't treat we can't treat you can't treat they can't treat
V-ing form
I can't be treating you can't be treating he can't be treating we can't be treating you can't be treating they can't be treating
Perfect
I can't have treated you can't have treated he can't have treated we can't have treated you can't have treated they can't have treated
V-ing perfect
I can't have been treating you can't have been treating he can't have been treating we can't have been treating you can't have been treating they can't have been treating
Interrogative form
Simple form
can I treat? can you treat? can he treat? can we treat? can you treat? can they treat?
V-ing form
can I be treating? can you be treating? can he be treating? can we be treating? can you be treating? can they be treating?
Perfect
can I have treated? can you have treated? can he have treated? can we have treated? can you have treated? can they have treated?
V-ing perfect
can I have been treating? can you have been treating? can he have been treating? can we have been treating? can you have been treating? can they have been treating?
Interro-negative form
Simple form
can't I treat? can't you treat? can't he treat? can't we treat? can't you treat? can't they treat?
V-ing form
can't I be treating? can't you be treating? can't he be treating? can't we be treating? can't you be treating? can't they be treating?
Perfect
can't I have treated? can't you have treated? can't he have treated? can't we have treated? can't you have treated? can't they have treated?
V-ing perfect
can't I have been treating? can't you have been treating? can't he have been treating? can't we have been treating? can't you have been treating? can't they have been treating?