I could just you could just he could just we could just you could just they could just
V-ing form
I could be justing you could be justing he could be justing we could be justing you could be justing they could be justing
Perfect
I could have justed you could have justed he could have justed we could have justed you could have justed they could have justed
V-ing perfect
I could have been justing you could have been justing he could have been justing we could have been justing you could have been justing they could have been justing
Negation
Simple form
I couldn't just you couldn't just he couldn't just we couldn't just you couldn't just they couldn't just
V-ing form
I couldn't be justing you couldn't be justing he couldn't be justing we couldn't be justing you couldn't be justing they couldn't be justing
Perfect
I couldn't have justed you couldn't have justed he couldn't have justed we couldn't have justed you couldn't have justed they couldn't have justed
V-ing perfect
I couldn't have been justing you couldn't have been justing he couldn't have been justing we couldn't have been justing you couldn't have been justing they couldn't have been justing
Interrogative form
Simple form
could I just? could you just? could he just? could we just? could you just? could they just?
V-ing form
could I be justing? could you be justing? could he be justing? could we be justing? could you be justing? could they be justing?
Perfect
could I have justed? could you have justed? could he have justed? could we have justed? could you have justed? could they have justed?
V-ing perfect
could I have been justing? could you have been justing? could he have been justing? could we have been justing? could you have been justing? could they have been justing?
Interro-negative form
Simple form
couldn't I just? couldn't you just? couldn't he just? couldn't we just? couldn't you just? couldn't they just?
V-ing form
couldn't I be justing? couldn't you be justing? couldn't he be justing? couldn't we be justing? couldn't you be justing? couldn't they be justing?
Perfect
couldn't I have justed? couldn't you have justed? couldn't he have justed? couldn't we have justed? couldn't you have justed? couldn't they have justed?
V-ing perfect
couldn't I have been justing? couldn't you have been justing? couldn't he have been justing? couldn't we have been justing? couldn't you have been justing? couldn't they have been justing?