English verb conjugation
SHOULD CONCENTRATE

Regular verb: concentrate - concentrated - concentrated

Affirmation

Simple form	V-ing form
I'd concentrate you'd concentrate he'd concentrate we'd concentrate you'd concentrate they'd concentrate	I'd be concentrating you'd be concentrating he'd be concentrating we'd be concentrating you'd be concentrating they'd be concentrating
Perfect	V-ing perfect
I should've concentrated you should've concentrated he should've concentrated we should've concentrated you should've concentrated they should've concentrated	I should've been concentrating you should've been concentrating he should've been concentrating we should've been concentrating you should've been concentrating they should've been concentrating

Negation

Simple form	V-ing form
I shouldn't concentrate you shouldn't concentrate he shouldn't concentrate we shouldn't concentrate you shouldn't concentrate they shouldn't concentrate	I shouldn't be concentrating you shouldn't be concentrating he shouldn't be concentrating we shouldn't be concentrating you shouldn't be concentrating they shouldn't be concentrating
Perfect	V-ing perfect
I shouldn't have concentrated you shouldn't have concentrated he shouldn't have concentrated we shouldn't have concentrated you shouldn't have concentrated they shouldn't have concentrated	I shouldn't have been concentrating you shouldn't have been concentrating he shouldn't have been concentrating we shouldn't have been concentrating you shouldn't have been concentrating they shouldn't have been concentrating

Interrogative form

Simple form	V-ing form
should I concentrate? should you concentrate? should he concentrate? should we concentrate? should you concentrate? should they concentrate?	should I be concentrating? should you be concentrating? should he be concentrating? should we be concentrating? should you be concentrating? should they be concentrating?
Perfect	V-ing perfect
should I have concentrated? should you have concentrated? should he have concentrated? should we have concentrated? should you have concentrated? should they have concentrated?	should I have been concentrating? should you have been concentrating? should he have been concentrating? should we have been concentrating? should you have been concentrating? should they have been concentrating?

Interro-negative form

Simple form	V-ing form
shouldn't I concentrate? shouldn't you concentrate? shouldn't he concentrate? shouldn't we concentrate? shouldn't you concentrate? shouldn't they concentrate?	shouldn't I be concentrating? shouldn't you be concentrating? shouldn't he be concentrating? shouldn't we be concentrating? shouldn't you be concentrating? shouldn't they be concentrating?
Perfect	V-ing perfect
shouldn't I have concentrated? shouldn't you have concentrated? shouldn't he have concentrated? shouldn't we have concentrated? shouldn't you have concentrated? shouldn't they have concentrated?	shouldn't I have been concentrating? shouldn't you have been concentrating? shouldn't he have been concentrating? shouldn't we have been concentrating? shouldn't you have been concentrating? shouldn't they have been concentrating?