should lengthen
Regular verb: lengthen - lengthened- lengthened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I'd lengthen
you'd lengthen
she'd lengthen
we'd lengthen
you'd lengthen
they'd lengthen 	I'd be lengthening
you'd be lengthening
she'd be lengthening
we'd be lengthening
you'd be lengthening
they'd be lengthening	I should've lengthened
you should've lengthened
she should've lengthened
we should've lengthened
you should've lengthened
they should've lengthened	I should've been lengthening
you should've been lengthening
she should've been lengthening
we should've been lengthening
you should've been lengthening
they should've been lengthening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I shouldn't lengthen
you shouldn't lengthen
she shouldn't lengthen
we shouldn't lengthen
you shouldn't lengthen
they shouldn't lengthen 	I shouldn't be lengthening
you shouldn't be lengthening
she shouldn't be lengthening
we shouldn't be lengthening
you shouldn't be lengthening
they shouldn't be lengthening	I shouldn't have lengthened
you shouldn't have lengthened
she shouldn't have lengthened
we shouldn't have lengthened
you shouldn't have lengthened
they shouldn't have lengthened	I shouldn't have been lengthening
you shouldn't have been lengthening
she shouldn't have been lengthening
we shouldn't have been lengthening
you shouldn't have been lengthening
they shouldn't have been lengthening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
should I lengthen?
should you lengthen?
should she lengthen?
should we lengthen?
should you lengthen?
should they lengthen? 	should I be lengthening?
should you be lengthening?
should she be lengthening?
should we be lengthening?
should you be lengthening?
should they be lengthening? 	should I have lengthened?
should you have lengthened?
should she have lengthened?
should we have lengthened?
should you have lengthened?
should they have lengthened? 	should I have been lengthening?
should you have been lengthening?
should she have been lengthening?
should we have been lengthening?
should you have been lengthening?
should they have been lengthening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
shouldn't I lengthen?
shouldn't you lengthen?
shouldn't she lengthen?
shouldn't we lengthen?
shouldn't you lengthen?
shouldn't they lengthen? 	shouldn't I be lengthening?
shouldn't you be lengthening?
shouldn't she be lengthening?
shouldn't we be lengthening?
shouldn't you be lengthening?
shouldn't they be lengthening? 	shouldn't I have lengthened?
shouldn't you have lengthened?
shouldn't she have lengthened?
shouldn't we have lengthened?
shouldn't you have lengthened?
shouldn't they have lengthened? 	shouldn't I have been lengthening?
shouldn't you have been lengthening?
shouldn't she have been lengthening?
shouldn't we have been lengthening?
shouldn't you have been lengthening?
shouldn't they have been lengthening?