Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could assign assign you could assign assign he could assign assign we could assign assign you could assign assign they could assign assign
V-ing form
I could be assign assigning you could be assign assigning he could be assign assigning we could be assign assigning you could be assign assigning they could be assign assigning
Perfect
I could have assign assigned you could have assign assigned he could have assign assigned we could have assign assigned you could have assign assigned they could have assign assigned
V-ing perfect
I could have been assign assigning you could have been assign assigning he could have been assign assigning we could have been assign assigning you could have been assign assigning they could have been assign assigning
Negation
Simple form
I couldn't assign assign you couldn't assign assign he couldn't assign assign we couldn't assign assign you couldn't assign assign they couldn't assign assign
V-ing form
I couldn't be assign assigning you couldn't be assign assigning he couldn't be assign assigning we couldn't be assign assigning you couldn't be assign assigning they couldn't be assign assigning
Perfect
I couldn't have assign assigned you couldn't have assign assigned he couldn't have assign assigned we couldn't have assign assigned you couldn't have assign assigned they couldn't have assign assigned
V-ing perfect
I couldn't have been assign assigning you couldn't have been assign assigning he couldn't have been assign assigning we couldn't have been assign assigning you couldn't have been assign assigning they couldn't have been assign assigning
Interrogative form
Simple form
could I assign assign? could you assign assign? could he assign assign? could we assign assign? could you assign assign? could they assign assign?
V-ing form
could I be assign assigning? could you be assign assigning? could he be assign assigning? could we be assign assigning? could you be assign assigning? could they be assign assigning?
Perfect
could I have assign assigned? could you have assign assigned? could he have assign assigned? could we have assign assigned? could you have assign assigned? could they have assign assigned?
V-ing perfect
could I have been assign assigning? could you have been assign assigning? could he have been assign assigning? could we have been assign assigning? could you have been assign assigning? could they have been assign assigning?
Interro-negative form
Simple form
couldn't I assign assign? couldn't you assign assign? couldn't he assign assign? couldn't we assign assign? couldn't you assign assign? couldn't they assign assign?
V-ing form
couldn't I be assign assigning? couldn't you be assign assigning? couldn't he be assign assigning? couldn't we be assign assigning? couldn't you be assign assigning? couldn't they be assign assigning?
Perfect
couldn't I have assign assigned? couldn't you have assign assigned? couldn't he have assign assigned? couldn't we have assign assigned? couldn't you have assign assigned? couldn't they have assign assigned?
V-ing perfect
couldn't I have been assign assigning? couldn't you have been assign assigning? couldn't he have been assign assigning? couldn't we have been assign assigning? couldn't you have been assign assigning? couldn't they have been assign assigning?