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