I should sit you should sit he should sit we should sit you should sit they should sit
V-ing form
I should be sitting you should be sitting he should be sitting we should be sitting you should be sitting they should be sitting
Perfect
I should have sat you should have sat he should have sat we should have sat you should have sat they should have sat
V-ing perfect
I should have been sitting you should have been sitting he should have been sitting we should have been sitting you should have been sitting they should have been sitting
Negation
Simple form
I should not sit you should not sit he should not sit we should not sit you should not sit they should not sit
V-ing form
I should not be sitting you should not be sitting he should not be sitting we should not be sitting you should not be sitting they should not be sitting
Perfect
I should not have sat you should not have sat he should not have sat we should not have sat you should not have sat they should not have sat
V-ing perfect
I should not have been sitting you should not have been sitting he should not have been sitting we should not have been sitting you should not have been sitting they should not have been sitting
Interrogative form
Simple form
should I sit? should you sit? should he sit? should we sit? should you sit? should they sit?
V-ing form
should I be sitting? should you be sitting? should he be sitting? should we be sitting? should you be sitting? should they be sitting?
Perfect
should I have sat? should you have sat? should he have sat? should we have sat? should you have sat? should they have sat?
V-ing perfect
should I have been sitting? should you have been sitting? should he have been sitting? should we have been sitting? should you have been sitting? should they have been sitting?
Interro-negative form
Simple form
should I not sit? should you not sit? should he not sit? should we not sit? should you not sit? should they not sit?
V-ing form
should I not be sitting? should you not be sitting? should he not be sitting? should we not be sitting? should you not be sitting? should they not be sitting?
Perfect
should I not have sat? should you not have sat? should he not have sat? should we not have sat? should you not have sat? should they not have sat?
V-ing perfect
should I not have been sitting? should you not have been sitting? should he not have been sitting? should we not have been sitting? should you not have been sitting? should they not have been sitting?