I should sum you should sum she should sum we should sum you should sum they should sum
V-ing form
I should be summing you should be summing she should be summing we should be summing you should be summing they should be summing
Perfect
I should have summed you should have summed she should have summed we should have summed you should have summed they should have summed
V-ing perfect
I should have been summing you should have been summing she should have been summing we should have been summing you should have been summing they should have been summing
Negation
Simple form
I should not sum you should not sum she should not sum we should not sum you should not sum they should not sum
V-ing form
I should not be summing you should not be summing she should not be summing we should not be summing you should not be summing they should not be summing
Perfect
I should not have summed you should not have summed she should not have summed we should not have summed you should not have summed they should not have summed
V-ing perfect
I should not have been summing you should not have been summing she should not have been summing we should not have been summing you should not have been summing they should not have been summing
Interrogative form
Simple form
should I sum? should you sum? should she sum? should we sum? should you sum? should they sum?
V-ing form
should I be summing? should you be summing? should she be summing? should we be summing? should you be summing? should they be summing?
Perfect
should I have summed? should you have summed? should she have summed? should we have summed? should you have summed? should they have summed?
V-ing perfect
should I have been summing? should you have been summing? should she have been summing? should we have been summing? should you have been summing? should they have been summing?
Interro-negative form
Simple form
should I not sum? should you not sum? should she not sum? should we not sum? should you not sum? should they not sum?
V-ing form
should I not be summing? should you not be summing? should she not be summing? should we not be summing? should you not be summing? should they not be summing?
Perfect
should I not have summed? should you not have summed? should she not have summed? should we not have summed? should you not have summed? should they not have summed?
V-ing perfect
should I not have been summing? should you not have been summing? should she not have been summing? should we not have been summing? should you not have been summing? should they not have been summing?