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 cannot treat you cannot treat he cannot treat we cannot treat you cannot treat they cannot treat
V-ing form
I cannot be treating you cannot be treating he cannot be treating we cannot be treating you cannot be treating they cannot be treating
Perfect
I cannot have treated you cannot have treated he cannot have treated we cannot have treated you cannot have treated they cannot have treated
V-ing perfect
I cannot have been treating you cannot have been treating he cannot have been treating we cannot have been treating you cannot have been treating they cannot 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 I not treat? can you not treat? can he not treat? can we not treat? can you not treat? can they not treat?
V-ing form
can I not be treating? can you not be treating? can he not be treating? can we not be treating? can you not be treating? can they not be treating?
Perfect
can I not have treated? can you not have treated? can he not have treated? can we not have treated? can you not have treated? can they not have treated?
V-ing perfect
can I not have been treating? can you not have been treating? can he not have been treating? can we not have been treating? can you not have been treating? can they not have been treating?