should flag
Regular verb: flag - flagged- flagged

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I'd flag
you'd flag
he'd flag
we'd flag
you'd flag
they'd flag 	I'd be flagging
you'd be flagging
he'd be flagging
we'd be flagging
you'd be flagging
they'd be flagging	I should've flagged
you should've flagged
he should've flagged
we should've flagged
you should've flagged
they should've flagged	I should've been flagging
you should've been flagging
he should've been flagging
we should've been flagging
you should've been flagging
they should've been flagging	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I shouldn't flag
you shouldn't flag
he shouldn't flag
we shouldn't flag
you shouldn't flag
they shouldn't flag 	I shouldn't be flagging
you shouldn't be flagging
he shouldn't be flagging
we shouldn't be flagging
you shouldn't be flagging
they shouldn't be flagging	I shouldn't have flagged
you shouldn't have flagged
he shouldn't have flagged
we shouldn't have flagged
you shouldn't have flagged
they shouldn't have flagged	I shouldn't have been flagging
you shouldn't have been flagging
he shouldn't have been flagging
we shouldn't have been flagging
you shouldn't have been flagging
they shouldn't have been flagging	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
should I flag?
should you flag?
should he flag?
should we flag?
should you flag?
should they flag? 	should I be flagging?
should you be flagging?
should he be flagging?
should we be flagging?
should you be flagging?
should they be flagging? 	should I have flagged?
should you have flagged?
should he have flagged?
should we have flagged?
should you have flagged?
should they have flagged? 	should I have been flagging?
should you have been flagging?
should he have been flagging?
should we have been flagging?
should you have been flagging?
should they have been flagging? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
shouldn't I flag?
shouldn't you flag?
shouldn't he flag?
shouldn't we flag?
shouldn't you flag?
shouldn't they flag? 	shouldn't I be flagging?
shouldn't you be flagging?
shouldn't he be flagging?
shouldn't we be flagging?
shouldn't you be flagging?
shouldn't they be flagging? 	shouldn't I have flagged?
shouldn't you have flagged?
shouldn't he have flagged?
shouldn't we have flagged?
shouldn't you have flagged?
shouldn't they have flagged? 	shouldn't I have been flagging?
shouldn't you have been flagging?
shouldn't he have been flagging?
shouldn't we have been flagging?
shouldn't you have been flagging?
shouldn't they have been flagging?