English verb conjugation
SHOULD BACK

Regular verb: back - backed - backed

Affirmation

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

Negation

Simple form	V-ing form
I should not back you should not back he should not back we should not back you should not back they should not back	I should not be backing you should not be backing he should not be backing we should not be backing you should not be backing they should not be backing
Perfect	V-ing perfect
I should not have backed you should not have backed he should not have backed we should not have backed you should not have backed they should not have backed	I should not have been backing you should not have been backing he should not have been backing we should not have been backing you should not have been backing they should not 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
should I not back? should you not back? should he not back? should we not back? should you not back? should they not back?	should I not be backing? should you not be backing? should he not be backing? should we not be backing? should you not be backing? should they not be backing?
Perfect	V-ing perfect
should I not have backed? should you not have backed? should he not have backed? should we not have backed? should you not have backed? should they not have backed?	should I not have been backing? should you not have been backing? should he not have been backing? should we not have been backing? should you not have been backing? should they not have been backing?