should exist
Regular verb: exist - existed- existed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I'd exist
you'd exist
she'd exist
we'd exist
you'd exist
they'd exist 	I'd be existing
you'd be existing
she'd be existing
we'd be existing
you'd be existing
they'd be existing	I should've existed
you should've existed
she should've existed
we should've existed
you should've existed
they should've existed	I should've been existing
you should've been existing
she should've been existing
we should've been existing
you should've been existing
they should've been existing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I shouldn't exist
you shouldn't exist
she shouldn't exist
we shouldn't exist
you shouldn't exist
they shouldn't exist 	I shouldn't be existing
you shouldn't be existing
she shouldn't be existing
we shouldn't be existing
you shouldn't be existing
they shouldn't be existing	I shouldn't have existed
you shouldn't have existed
she shouldn't have existed
we shouldn't have existed
you shouldn't have existed
they shouldn't have existed	I shouldn't have been existing
you shouldn't have been existing
she shouldn't have been existing
we shouldn't have been existing
you shouldn't have been existing
they shouldn't have been existing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
should I exist?
should you exist?
should she exist?
should we exist?
should you exist?
should they exist? 	should I be existing?
should you be existing?
should she be existing?
should we be existing?
should you be existing?
should they be existing? 	should I have existed?
should you have existed?
should she have existed?
should we have existed?
should you have existed?
should they have existed? 	should I have been existing?
should you have been existing?
should she have been existing?
should we have been existing?
should you have been existing?
should they have been existing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
shouldn't I exist?
shouldn't you exist?
shouldn't she exist?
shouldn't we exist?
shouldn't you exist?
shouldn't they exist? 	shouldn't I be existing?
shouldn't you be existing?
shouldn't she be existing?
shouldn't we be existing?
shouldn't you be existing?
shouldn't they be existing? 	shouldn't I have existed?
shouldn't you have existed?
shouldn't she have existed?
shouldn't we have existed?
shouldn't you have existed?
shouldn't they have existed? 	shouldn't I have been existing?
shouldn't you have been existing?
shouldn't she have been existing?
shouldn't we have been existing?
shouldn't you have been existing?
shouldn't they have been existing?