English verb conjugation
SHOULD BACK

Regular verb: back - backed - backed

Affirmation

Simple form	V-ing form
I'd back you'd back he'd back we'd back you'd back they'd back	I'd be backing you'd be backing he'd be backing we'd be backing you'd be backing they'd be backing
Perfect	V-ing perfect
I should've backed you should've backed he should've backed we should've backed you should've backed they should've backed	I should've been backing you should've been backing he should've been backing we should've been backing you should've been backing they should've been backing

Negation

Simple form	V-ing form
I shouldn't back you shouldn't back he shouldn't back we shouldn't back you shouldn't back they shouldn't back	I shouldn't be backing you shouldn't be backing he shouldn't be backing we shouldn't be backing you shouldn't be backing they shouldn't be backing
Perfect	V-ing perfect
I shouldn't have backed you shouldn't have backed he shouldn't have backed we shouldn't have backed you shouldn't have backed they shouldn't have backed	I shouldn't have been backing you shouldn't have been backing he shouldn't have been backing we shouldn't have been backing you shouldn't have been backing they shouldn't have been backing

Interrogative form

Simple form	V-ing form
should I back? should you back? should he back? should we back? should you back? should they back?	should I be backing? should you be backing? should he be backing? should we be backing? should you be backing? should they be backing?
Perfect	V-ing perfect
should I have backed? should you have backed? should he have backed? should we have backed? should you have backed? should they have backed?	should I have been backing? should you have been backing? should he have been backing? should we have been backing? should you have been backing? should they have been backing?

Interro-negative form

Simple form	V-ing form
shouldn't I back? shouldn't you back? shouldn't he back? shouldn't we back? shouldn't you back? shouldn't they back?	shouldn't I be backing? shouldn't you be backing? shouldn't he be backing? shouldn't we be backing? shouldn't you be backing? shouldn't they be backing?
Perfect	V-ing perfect
shouldn't I have backed? shouldn't you have backed? shouldn't he have backed? shouldn't we have backed? shouldn't you have backed? shouldn't they have backed?	shouldn't I have been backing? shouldn't you have been backing? shouldn't he have been backing? shouldn't we have been backing? shouldn't you have been backing? shouldn't they have been backing?