I could erode you could erode she could erode we could erode you could erode they could erode
V-ing form
I could be eroding you could be eroding she could be eroding we could be eroding you could be eroding they could be eroding
Perfect
I could have eroded you could have eroded she could have eroded we could have eroded you could have eroded they could have eroded
V-ing perfect
I could have been eroding you could have been eroding she could have been eroding we could have been eroding you could have been eroding they could have been eroding
Negation
Simple form
I couldn't erode you couldn't erode she couldn't erode we couldn't erode you couldn't erode they couldn't erode
V-ing form
I couldn't be eroding you couldn't be eroding she couldn't be eroding we couldn't be eroding you couldn't be eroding they couldn't be eroding
Perfect
I couldn't have eroded you couldn't have eroded she couldn't have eroded we couldn't have eroded you couldn't have eroded they couldn't have eroded
V-ing perfect
I couldn't have been eroding you couldn't have been eroding she couldn't have been eroding we couldn't have been eroding you couldn't have been eroding they couldn't have been eroding
Interrogative form
Simple form
could I erode? could you erode? could she erode? could we erode? could you erode? could they erode?
V-ing form
could I be eroding? could you be eroding? could she be eroding? could we be eroding? could you be eroding? could they be eroding?
Perfect
could I have eroded? could you have eroded? could she have eroded? could we have eroded? could you have eroded? could they have eroded?
V-ing perfect
could I have been eroding? could you have been eroding? could she have been eroding? could we have been eroding? could you have been eroding? could they have been eroding?
Interro-negative form
Simple form
couldn't I erode? couldn't you erode? couldn't she erode? couldn't we erode? couldn't you erode? couldn't they erode?
V-ing form
couldn't I be eroding? couldn't you be eroding? couldn't she be eroding? couldn't we be eroding? couldn't you be eroding? couldn't they be eroding?
Perfect
couldn't I have eroded? couldn't you have eroded? couldn't she have eroded? couldn't we have eroded? couldn't you have eroded? couldn't they have eroded?
V-ing perfect
couldn't I have been eroding? couldn't you have been eroding? couldn't she have been eroding? couldn't we have been eroding? couldn't you have been eroding? couldn't they have been eroding?