I'd be backcrossing you'd be backcrossing he'd be backcrossing we'd be backcrossing you'd be backcrossing they'd be backcrossing
Perfect
I should've backcrossed you should've backcrossed he should've backcrossed we should've backcrossed you should've backcrossed they should've backcrossed
V-ing perfect
I should've been backcrossing you should've been backcrossing he should've been backcrossing we should've been backcrossing you should've been backcrossing they should've been backcrossing
Negation
Simple form
I shouldn't backcross you shouldn't backcross he shouldn't backcross we shouldn't backcross you shouldn't backcross they shouldn't backcross
V-ing form
I shouldn't be backcrossing you shouldn't be backcrossing he shouldn't be backcrossing we shouldn't be backcrossing you shouldn't be backcrossing they shouldn't be backcrossing
Perfect
I shouldn't have backcrossed you shouldn't have backcrossed he shouldn't have backcrossed we shouldn't have backcrossed you shouldn't have backcrossed they shouldn't have backcrossed
V-ing perfect
I shouldn't have been backcrossing you shouldn't have been backcrossing he shouldn't have been backcrossing we shouldn't have been backcrossing you shouldn't have been backcrossing they shouldn't have been backcrossing
Interrogative form
Simple form
should I backcross? should you backcross? should he backcross? should we backcross? should you backcross? should they backcross?
V-ing form
should I be backcrossing? should you be backcrossing? should he be backcrossing? should we be backcrossing? should you be backcrossing? should they be backcrossing?
Perfect
should I have backcrossed? should you have backcrossed? should he have backcrossed? should we have backcrossed? should you have backcrossed? should they have backcrossed?
V-ing perfect
should I have been backcrossing? should you have been backcrossing? should he have been backcrossing? should we have been backcrossing? should you have been backcrossing? should they have been backcrossing?
Interro-negative form
Simple form
shouldn't I backcross? shouldn't you backcross? shouldn't he backcross? shouldn't we backcross? shouldn't you backcross? shouldn't they backcross?
V-ing form
shouldn't I be backcrossing? shouldn't you be backcrossing? shouldn't he be backcrossing? shouldn't we be backcrossing? shouldn't you be backcrossing? shouldn't they be backcrossing?
Perfect
shouldn't I have backcrossed? shouldn't you have backcrossed? shouldn't he have backcrossed? shouldn't we have backcrossed? shouldn't you have backcrossed? shouldn't they have backcrossed?
V-ing perfect
shouldn't I have been backcrossing? shouldn't you have been backcrossing? shouldn't he have been backcrossing? shouldn't we have been backcrossing? shouldn't you have been backcrossing? shouldn't they have been backcrossing?