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