I can guard you can guard she can guard we can guard you can guard they can guard
V-ing form
I can be guarding you can be guarding she can be guarding we can be guarding you can be guarding they can be guarding
Perfect
I can have guarded you can have guarded she can have guarded we can have guarded you can have guarded they can have guarded
V-ing perfect
I can have been guarding you can have been guarding she can have been guarding we can have been guarding you can have been guarding they can have been guarding
Negation
Simple form
I cannot guard you cannot guard she cannot guard we cannot guard you cannot guard they cannot guard
V-ing form
I cannot be guarding you cannot be guarding she cannot be guarding we cannot be guarding you cannot be guarding they cannot be guarding
Perfect
I cannot have guarded you cannot have guarded she cannot have guarded we cannot have guarded you cannot have guarded they cannot have guarded
V-ing perfect
I cannot have been guarding you cannot have been guarding she cannot have been guarding we cannot have been guarding you cannot have been guarding they cannot have been guarding
Interrogative form
Simple form
can I guard? can you guard? can she guard? can we guard? can you guard? can they guard?
V-ing form
can I be guarding? can you be guarding? can she be guarding? can we be guarding? can you be guarding? can they be guarding?
Perfect
can I have guarded? can you have guarded? can she have guarded? can we have guarded? can you have guarded? can they have guarded?
V-ing perfect
can I have been guarding? can you have been guarding? can she have been guarding? can we have been guarding? can you have been guarding? can they have been guarding?
Interro-negative form
Simple form
can I not guard? can you not guard? can she not guard? can we not guard? can you not guard? can they not guard?
V-ing form
can I not be guarding? can you not be guarding? can she not be guarding? can we not be guarding? can you not be guarding? can they not be guarding?
Perfect
can I not have guarded? can you not have guarded? can she not have guarded? can we not have guarded? can you not have guarded? can they not have guarded?
V-ing perfect
can I not have been guarding? can you not have been guarding? can she not have been guarding? can we not have been guarding? can you not have been guarding? can they not have been guarding?