Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could envy envy you could envy envy he could envy envy we could envy envy you could envy envy they could envy envy
V-ing form
I could be envy envying you could be envy envying he could be envy envying we could be envy envying you could be envy envying they could be envy envying
Perfect
I could have envy envied you could have envy envied he could have envy envied we could have envy envied you could have envy envied they could have envy envied
V-ing perfect
I could have been envy envying you could have been envy envying he could have been envy envying we could have been envy envying you could have been envy envying they could have been envy envying
Negation
Simple form
I could not envy envy you could not envy envy he could not envy envy we could not envy envy you could not envy envy they could not envy envy
V-ing form
I could not be envy envying you could not be envy envying he could not be envy envying we could not be envy envying you could not be envy envying they could not be envy envying
Perfect
I could not have envy envied you could not have envy envied he could not have envy envied we could not have envy envied you could not have envy envied they could not have envy envied
V-ing perfect
I could not have been envy envying you could not have been envy envying he could not have been envy envying we could not have been envy envying you could not have been envy envying they could not have been envy envying
Interrogative form
Simple form
could I envy envy? could you envy envy? could he envy envy? could we envy envy? could you envy envy? could they envy envy?
V-ing form
could I be envy envying? could you be envy envying? could he be envy envying? could we be envy envying? could you be envy envying? could they be envy envying?
Perfect
could I have envy envied? could you have envy envied? could he have envy envied? could we have envy envied? could you have envy envied? could they have envy envied?
V-ing perfect
could I have been envy envying? could you have been envy envying? could he have been envy envying? could we have been envy envying? could you have been envy envying? could they have been envy envying?
Interro-negative form
Simple form
could I not envy envy? could you not envy envy? could he not envy envy? could we not envy envy? could you not envy envy? could they not envy envy?
V-ing form
could I not be envy envying? could you not be envy envying? could he not be envy envying? could we not be envy envying? could you not be envy envying? could they not be envy envying?
Perfect
could I not have envy envied? could you not have envy envied? could he not have envy envied? could we not have envy envied? could you not have envy envied? could they not have envy envied?
V-ing perfect
could I not have been envy envying? could you not have been envy envying? could he not have been envy envying? could we not have been envy envying? could you not have been envy envying? could they not have been envy envying?