I could corrode you could corrode he could corrode we could corrode you could corrode they could corrode
V-ing form
I could be corroding you could be corroding he could be corroding we could be corroding you could be corroding they could be corroding
Perfect
I could have corroded you could have corroded he could have corroded we could have corroded you could have corroded they could have corroded
V-ing perfect
I could have been corroding you could have been corroding he could have been corroding we could have been corroding you could have been corroding they could have been corroding
Negation
Simple form
I couldn't corrode you couldn't corrode he couldn't corrode we couldn't corrode you couldn't corrode they couldn't corrode
V-ing form
I couldn't be corroding you couldn't be corroding he couldn't be corroding we couldn't be corroding you couldn't be corroding they couldn't be corroding
Perfect
I couldn't have corroded you couldn't have corroded he couldn't have corroded we couldn't have corroded you couldn't have corroded they couldn't have corroded
V-ing perfect
I couldn't have been corroding you couldn't have been corroding he couldn't have been corroding we couldn't have been corroding you couldn't have been corroding they couldn't have been corroding
Interrogative form
Simple form
could I corrode? could you corrode? could he corrode? could we corrode? could you corrode? could they corrode?
V-ing form
could I be corroding? could you be corroding? could he be corroding? could we be corroding? could you be corroding? could they be corroding?
Perfect
could I have corroded? could you have corroded? could he have corroded? could we have corroded? could you have corroded? could they have corroded?
V-ing perfect
could I have been corroding? could you have been corroding? could he have been corroding? could we have been corroding? could you have been corroding? could they have been corroding?
Interro-negative form
Simple form
couldn't I corrode? couldn't you corrode? couldn't he corrode? couldn't we corrode? couldn't you corrode? couldn't they corrode?
V-ing form
couldn't I be corroding? couldn't you be corroding? couldn't he be corroding? couldn't we be corroding? couldn't you be corroding? couldn't they be corroding?
Perfect
couldn't I have corroded? couldn't you have corroded? couldn't he have corroded? couldn't we have corroded? couldn't you have corroded? couldn't they have corroded?
V-ing perfect
couldn't I have been corroding? couldn't you have been corroding? couldn't he have been corroding? couldn't we have been corroding? couldn't you have been corroding? couldn't they have been corroding?