English verb conjugation
SHOULD VARY

Regular verb: vary - varied - varied

Affirmation

Simple form	V-ing form
I'd vary you'd vary he'd vary we'd vary you'd vary they'd vary	I'd be varying you'd be varying he'd be varying we'd be varying you'd be varying they'd be varying
Perfect	V-ing perfect
I should've varied you should've varied he should've varied we should've varied you should've varied they should've varied	I should've been varying you should've been varying he should've been varying we should've been varying you should've been varying they should've been varying

Negation

Simple form	V-ing form
I shouldn't vary you shouldn't vary he shouldn't vary we shouldn't vary you shouldn't vary they shouldn't vary	I shouldn't be varying you shouldn't be varying he shouldn't be varying we shouldn't be varying you shouldn't be varying they shouldn't be varying
Perfect	V-ing perfect
I shouldn't have varied you shouldn't have varied he shouldn't have varied we shouldn't have varied you shouldn't have varied they shouldn't have varied	I shouldn't have been varying you shouldn't have been varying he shouldn't have been varying we shouldn't have been varying you shouldn't have been varying they shouldn't have been varying

Interrogative form

Simple form	V-ing form
should I vary? should you vary? should he vary? should we vary? should you vary? should they vary?	should I be varying? should you be varying? should he be varying? should we be varying? should you be varying? should they be varying?
Perfect	V-ing perfect
should I have varied? should you have varied? should he have varied? should we have varied? should you have varied? should they have varied?	should I have been varying? should you have been varying? should he have been varying? should we have been varying? should you have been varying? should they have been varying?

Interro-negative form

Simple form	V-ing form
shouldn't I vary? shouldn't you vary? shouldn't he vary? shouldn't we vary? shouldn't you vary? shouldn't they vary?	shouldn't I be varying? shouldn't you be varying? shouldn't he be varying? shouldn't we be varying? shouldn't you be varying? shouldn't they be varying?
Perfect	V-ing perfect
shouldn't I have varied? shouldn't you have varied? shouldn't he have varied? shouldn't we have varied? shouldn't you have varied? shouldn't they have varied?	shouldn't I have been varying? shouldn't you have been varying? shouldn't he have been varying? shouldn't we have been varying? shouldn't you have been varying? shouldn't they have been varying?