I could assign you could assign he could assign we could assign you could assign they could assign
V-ing form
I could be assigning you could be assigning he could be assigning we could be assigning you could be assigning they could be assigning
Perfect
I could have assigned you could have assigned he could have assigned we could have assigned you could have assigned they could have assigned
V-ing perfect
I could have been assigning you could have been assigning he could have been assigning we could have been assigning you could have been assigning they could have been assigning
Negation
Simple form
I could not assign you could not assign he could not assign we could not assign you could not assign they could not assign
V-ing form
I could not be assigning you could not be assigning he could not be assigning we could not be assigning you could not be assigning they could not be assigning
Perfect
I could not have assigned you could not have assigned he could not have assigned we could not have assigned you could not have assigned they could not have assigned
V-ing perfect
I could not have been assigning you could not have been assigning he could not have been assigning we could not have been assigning you could not have been assigning they could not have been assigning
Interrogative form
Simple form
could I assign? could you assign? could he assign? could we assign? could you assign? could they assign?
V-ing form
could I be assigning? could you be assigning? could he be assigning? could we be assigning? could you be assigning? could they be assigning?
Perfect
could I have assigned? could you have assigned? could he have assigned? could we have assigned? could you have assigned? could they have assigned?
V-ing perfect
could I have been assigning? could you have been assigning? could he have been assigning? could we have been assigning? could you have been assigning? could they have been assigning?
Interro-negative form
Simple form
could I not assign? could you not assign? could he not assign? could we not assign? could you not assign? could they not assign?
V-ing form
could I not be assigning? could you not be assigning? could he not be assigning? could we not be assigning? could you not be assigning? could they not be assigning?
Perfect
could I not have assigned? could you not have assigned? could he not have assigned? could we not have assigned? could you not have assigned? could they not have assigned?
V-ing perfect
could I not have been assigning? could you not have been assigning? could he not have been assigning? could we not have been assigning? could you not have been assigning? could they not have been assigning?