I should stack you should stack she should stack we should stack you should stack they should stack
V-ing form
I should be stacking you should be stacking she should be stacking we should be stacking you should be stacking they should be stacking
Perfect
I should have stacked you should have stacked she should have stacked we should have stacked you should have stacked they should have stacked
V-ing perfect
I should have been stacking you should have been stacking she should have been stacking we should have been stacking you should have been stacking they should have been stacking
Negation
Simple form
I should not stack you should not stack she should not stack we should not stack you should not stack they should not stack
V-ing form
I should not be stacking you should not be stacking she should not be stacking we should not be stacking you should not be stacking they should not be stacking
Perfect
I should not have stacked you should not have stacked she should not have stacked we should not have stacked you should not have stacked they should not have stacked
V-ing perfect
I should not have been stacking you should not have been stacking she should not have been stacking we should not have been stacking you should not have been stacking they should not have been stacking
Interrogative form
Simple form
should I stack? should you stack? should she stack? should we stack? should you stack? should they stack?
V-ing form
should I be stacking? should you be stacking? should she be stacking? should we be stacking? should you be stacking? should they be stacking?
Perfect
should I have stacked? should you have stacked? should she have stacked? should we have stacked? should you have stacked? should they have stacked?
V-ing perfect
should I have been stacking? should you have been stacking? should she have been stacking? should we have been stacking? should you have been stacking? should they have been stacking?
Interro-negative form
Simple form
should I not stack? should you not stack? should she not stack? should we not stack? should you not stack? should they not stack?
V-ing form
should I not be stacking? should you not be stacking? should she not be stacking? should we not be stacking? should you not be stacking? should they not be stacking?
Perfect
should I not have stacked? should you not have stacked? should she not have stacked? should we not have stacked? should you not have stacked? should they not have stacked?
V-ing perfect
should I not have been stacking? should you not have been stacking? should she not have been stacking? should we not have been stacking? should you not have been stacking? should they not have been stacking?