English verb conjugation
SHOULD UNDERPIN

Regular verb: underpin - underpinned - underpinned

Affirmation

Simple form	V-ing form
I'd underpin you'd underpin he'd underpin we'd underpin you'd underpin they'd underpin	I'd be underpinning you'd be underpinning he'd be underpinning we'd be underpinning you'd be underpinning they'd be underpinning
Perfect	V-ing perfect
I should've underpinned you should've underpinned he should've underpinned we should've underpinned you should've underpinned they should've underpinned	I should've been underpinning you should've been underpinning he should've been underpinning we should've been underpinning you should've been underpinning they should've been underpinning

Negation

Simple form	V-ing form
I shouldn't underpin you shouldn't underpin he shouldn't underpin we shouldn't underpin you shouldn't underpin they shouldn't underpin	I shouldn't be underpinning you shouldn't be underpinning he shouldn't be underpinning we shouldn't be underpinning you shouldn't be underpinning they shouldn't be underpinning
Perfect	V-ing perfect
I shouldn't have underpinned you shouldn't have underpinned he shouldn't have underpinned we shouldn't have underpinned you shouldn't have underpinned they shouldn't have underpinned	I shouldn't have been underpinning you shouldn't have been underpinning he shouldn't have been underpinning we shouldn't have been underpinning you shouldn't have been underpinning they shouldn't have been underpinning

Interrogative form

Simple form	V-ing form
should I underpin? should you underpin? should he underpin? should we underpin? should you underpin? should they underpin?	should I be underpinning? should you be underpinning? should he be underpinning? should we be underpinning? should you be underpinning? should they be underpinning?
Perfect	V-ing perfect
should I have underpinned? should you have underpinned? should he have underpinned? should we have underpinned? should you have underpinned? should they have underpinned?	should I have been underpinning? should you have been underpinning? should he have been underpinning? should we have been underpinning? should you have been underpinning? should they have been underpinning?

Interro-negative form

Simple form	V-ing form
shouldn't I underpin? shouldn't you underpin? shouldn't he underpin? shouldn't we underpin? shouldn't you underpin? shouldn't they underpin?	shouldn't I be underpinning? shouldn't you be underpinning? shouldn't he be underpinning? shouldn't we be underpinning? shouldn't you be underpinning? shouldn't they be underpinning?
Perfect	V-ing perfect
shouldn't I have underpinned? shouldn't you have underpinned? shouldn't he have underpinned? shouldn't we have underpinned? shouldn't you have underpinned? shouldn't they have underpinned?	shouldn't I have been underpinning? shouldn't you have been underpinning? shouldn't he have been underpinning? shouldn't we have been underpinning? shouldn't you have been underpinning? shouldn't they have been underpinning?