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 could not just you could not just he could not just we could not just you could not just they could not just
V-ing form
I could not be justing you could not be justing he could not be justing we could not be justing you could not be justing they could not be justing
Perfect
I could not have justed you could not have justed he could not have justed we could not have justed you could not have justed they could not have justed
V-ing perfect
I could not have been justing you could not have been justing he could not have been justing we could not have been justing you could not have been justing they could not 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
could I not just? could you not just? could he not just? could we not just? could you not just? could they not just?
V-ing form
could I not be justing? could you not be justing? could he not be justing? could we not be justing? could you not be justing? could they not be justing?
Perfect
could I not have justed? could you not have justed? could he not have justed? could we not have justed? could you not have justed? could they not have justed?
V-ing perfect
could I not have been justing? could you not have been justing? could he not have been justing? could we not have been justing? could you not have been justing? could they not have been justing?