should darken
Regular verb: darken - darkened- darkened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I'd darken
you'd darken
she'd darken
we'd darken
you'd darken
they'd darken 	I'd be darkening
you'd be darkening
she'd be darkening
we'd be darkening
you'd be darkening
they'd be darkening	I should've darkened
you should've darkened
she should've darkened
we should've darkened
you should've darkened
they should've darkened	I should've been darkening
you should've been darkening
she should've been darkening
we should've been darkening
you should've been darkening
they should've been darkening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I shouldn't darken
you shouldn't darken
she shouldn't darken
we shouldn't darken
you shouldn't darken
they shouldn't darken 	I shouldn't be darkening
you shouldn't be darkening
she shouldn't be darkening
we shouldn't be darkening
you shouldn't be darkening
they shouldn't be darkening	I shouldn't have darkened
you shouldn't have darkened
she shouldn't have darkened
we shouldn't have darkened
you shouldn't have darkened
they shouldn't have darkened	I shouldn't have been darkening
you shouldn't have been darkening
she shouldn't have been darkening
we shouldn't have been darkening
you shouldn't have been darkening
they shouldn't have been darkening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
should I darken?
should you darken?
should she darken?
should we darken?
should you darken?
should they darken? 	should I be darkening?
should you be darkening?
should she be darkening?
should we be darkening?
should you be darkening?
should they be darkening? 	should I have darkened?
should you have darkened?
should she have darkened?
should we have darkened?
should you have darkened?
should they have darkened? 	should I have been darkening?
should you have been darkening?
should she have been darkening?
should we have been darkening?
should you have been darkening?
should they have been darkening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
shouldn't I darken?
shouldn't you darken?
shouldn't she darken?
shouldn't we darken?
shouldn't you darken?
shouldn't they darken? 	shouldn't I be darkening?
shouldn't you be darkening?
shouldn't she be darkening?
shouldn't we be darkening?
shouldn't you be darkening?
shouldn't they be darkening? 	shouldn't I have darkened?
shouldn't you have darkened?
shouldn't she have darkened?
shouldn't we have darkened?
shouldn't you have darkened?
shouldn't they have darkened? 	shouldn't I have been darkening?
shouldn't you have been darkening?
shouldn't she have been darkening?
shouldn't we have been darkening?
shouldn't you have been darkening?
shouldn't they have been darkening?