English verb conjugation
SHOULD TIFF

Regular verb: tiff - tiffed - tiffed

Affirmation

Simple form	V-ing form
I'd tiff you'd tiff she'd tiff we'd tiff you'd tiff they'd tiff	I'd be tiffing you'd be tiffing she'd be tiffing we'd be tiffing you'd be tiffing they'd be tiffing
Perfect	V-ing perfect
I should've tiffed you should've tiffed she should've tiffed we should've tiffed you should've tiffed they should've tiffed	I should've been tiffing you should've been tiffing she should've been tiffing we should've been tiffing you should've been tiffing they should've been tiffing

Negation

Simple form	V-ing form
I shouldn't tiff you shouldn't tiff she shouldn't tiff we shouldn't tiff you shouldn't tiff they shouldn't tiff	I shouldn't be tiffing you shouldn't be tiffing she shouldn't be tiffing we shouldn't be tiffing you shouldn't be tiffing they shouldn't be tiffing
Perfect	V-ing perfect
I shouldn't have tiffed you shouldn't have tiffed she shouldn't have tiffed we shouldn't have tiffed you shouldn't have tiffed they shouldn't have tiffed	I shouldn't have been tiffing you shouldn't have been tiffing she shouldn't have been tiffing we shouldn't have been tiffing you shouldn't have been tiffing they shouldn't have been tiffing

Interrogative form

Simple form	V-ing form
should I tiff? should you tiff? should she tiff? should we tiff? should you tiff? should they tiff?	should I be tiffing? should you be tiffing? should she be tiffing? should we be tiffing? should you be tiffing? should they be tiffing?
Perfect	V-ing perfect
should I have tiffed? should you have tiffed? should she have tiffed? should we have tiffed? should you have tiffed? should they have tiffed?	should I have been tiffing? should you have been tiffing? should she have been tiffing? should we have been tiffing? should you have been tiffing? should they have been tiffing?

Interro-negative form

Simple form	V-ing form
shouldn't I tiff? shouldn't you tiff? shouldn't she tiff? shouldn't we tiff? shouldn't you tiff? shouldn't they tiff?	shouldn't I be tiffing? shouldn't you be tiffing? shouldn't she be tiffing? shouldn't we be tiffing? shouldn't you be tiffing? shouldn't they be tiffing?
Perfect	V-ing perfect
shouldn't I have tiffed? shouldn't you have tiffed? shouldn't she have tiffed? shouldn't we have tiffed? shouldn't you have tiffed? shouldn't they have tiffed?	shouldn't I have been tiffing? shouldn't you have been tiffing? shouldn't she have been tiffing? shouldn't we have been tiffing? shouldn't you have been tiffing? shouldn't they have been tiffing?