I could defend you could defend she could defend we could defend you could defend they could defend
V-ing form
I could be defending you could be defending she could be defending we could be defending you could be defending they could be defending
Perfect
I could have defended you could have defended she could have defended we could have defended you could have defended they could have defended
V-ing perfect
I could have been defending you could have been defending she could have been defending we could have been defending you could have been defending they could have been defending
Negation
Simple form
I could not defend you could not defend she could not defend we could not defend you could not defend they could not defend
V-ing form
I could not be defending you could not be defending she could not be defending we could not be defending you could not be defending they could not be defending
Perfect
I could not have defended you could not have defended she could not have defended we could not have defended you could not have defended they could not have defended
V-ing perfect
I could not have been defending you could not have been defending she could not have been defending we could not have been defending you could not have been defending they could not have been defending
Interrogative form
Simple form
could I defend? could you defend? could she defend? could we defend? could you defend? could they defend?
V-ing form
could I be defending? could you be defending? could she be defending? could we be defending? could you be defending? could they be defending?
Perfect
could I have defended? could you have defended? could she have defended? could we have defended? could you have defended? could they have defended?
V-ing perfect
could I have been defending? could you have been defending? could she have been defending? could we have been defending? could you have been defending? could they have been defending?
Interro-negative form
Simple form
could I not defend? could you not defend? could she not defend? could we not defend? could you not defend? could they not defend?
V-ing form
could I not be defending? could you not be defending? could she not be defending? could we not be defending? could you not be defending? could they not be defending?
Perfect
could I not have defended? could you not have defended? could she not have defended? could we not have defended? could you not have defended? could they not have defended?
V-ing perfect
could I not have been defending? could you not have been defending? could she not have been defending? could we not have been defending? could you not have been defending? could they not have been defending?