could erode
Regular verb: erode - eroded- eroded

Affirmation 	
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I could erode
you could erode
he could erode
we could erode
you could erode
they could erode 	I could be eroding
you could be eroding
he could be eroding
we could be eroding
you could be eroding
they could be eroding	I could have eroded
you could have eroded
he could have eroded
we could have eroded
you could have eroded
they could have eroded	I could have been eroding
you could have been eroding
he could have been eroding
we could have been eroding
you could have been eroding
they could have been eroding	

Negation 	
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I couldn't erode
you couldn't erode
he couldn't erode
we couldn't erode
you couldn't erode
they couldn't erode 	I couldn't be eroding
you couldn't be eroding
he couldn't be eroding
we couldn't be eroding
you couldn't be eroding
they couldn't be eroding	I couldn't have eroded
you couldn't have eroded
he couldn't have eroded
we couldn't have eroded
you couldn't have eroded
they couldn't have eroded	I couldn't have been eroding
you couldn't have been eroding
he 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 	
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could I erode?
could you erode?
could he erode?
could we erode?
could you erode?
could they erode? 	could I be eroding?
could you be eroding?
could he be eroding?
could we be eroding?
could you be eroding?
could they be eroding? 	could I have eroded?
could you have eroded?
could he have eroded?
could we have eroded?
could you have eroded?
could they have eroded? 	could I have been eroding?
could you have been eroding?
could he have been eroding?
could we have been eroding?
could you have been eroding?
could they have been eroding? 	

Interro-negative form 	
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couldn't I erode?
couldn't you erode?
couldn't he erode?
couldn't we erode?
couldn't you erode?
couldn't they erode? 	couldn't I be eroding?
couldn't you be eroding?
couldn't he be eroding?
couldn't we be eroding?
couldn't you be eroding?
couldn't they be eroding? 	couldn't I have eroded?
couldn't you have eroded?
couldn't he have eroded?
couldn't we have eroded?
couldn't you have eroded?
couldn't they have eroded? 	couldn't I have been eroding?
couldn't you have been eroding?
couldn't he have been eroding?
couldn't we have been eroding?
couldn't you have been eroding?
couldn't they have been eroding?