I should center you should center he should center we should center you should center they should center
V-ing form
I should be centering you should be centering he should be centering we should be centering you should be centering they should be centering
Perfect
I should have centered you should have centered he should have centered we should have centered you should have centered they should have centered
V-ing perfect
I should have been centering you should have been centering he should have been centering we should have been centering you should have been centering they should have been centering
Negation
Simple form
I should not center you should not center he should not center we should not center you should not center they should not center
V-ing form
I should not be centering you should not be centering he should not be centering we should not be centering you should not be centering they should not be centering
Perfect
I should not have centered you should not have centered he should not have centered we should not have centered you should not have centered they should not have centered
V-ing perfect
I should not have been centering you should not have been centering he should not have been centering we should not have been centering you should not have been centering they should not have been centering
Interrogative form
Simple form
should I center? should you center? should he center? should we center? should you center? should they center?
V-ing form
should I be centering? should you be centering? should he be centering? should we be centering? should you be centering? should they be centering?
Perfect
should I have centered? should you have centered? should he have centered? should we have centered? should you have centered? should they have centered?
V-ing perfect
should I have been centering? should you have been centering? should he have been centering? should we have been centering? should you have been centering? should they have been centering?
Interro-negative form
Simple form
should I not center? should you not center? should he not center? should we not center? should you not center? should they not center?
V-ing form
should I not be centering? should you not be centering? should he not be centering? should we not be centering? should you not be centering? should they not be centering?
Perfect
should I not have centered? should you not have centered? should he not have centered? should we not have centered? should you not have centered? should they not have centered?
V-ing perfect
should I not have been centering? should you not have been centering? should he not have been centering? should we not have been centering? should you not have been centering? should they not have been centering?