should challenge
Regular verb: challenge - challenged- challenged

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I'd challenge
you'd challenge
she'd challenge
we'd challenge
you'd challenge
they'd challenge 	I'd be challenging
you'd be challenging
she'd be challenging
we'd be challenging
you'd be challenging
they'd be challenging	I should've challenged
you should've challenged
she should've challenged
we should've challenged
you should've challenged
they should've challenged	I should've been challenging
you should've been challenging
she should've been challenging
we should've been challenging
you should've been challenging
they should've been challenging	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I shouldn't challenge
you shouldn't challenge
she shouldn't challenge
we shouldn't challenge
you shouldn't challenge
they shouldn't challenge 	I shouldn't be challenging
you shouldn't be challenging
she shouldn't be challenging
we shouldn't be challenging
you shouldn't be challenging
they shouldn't be challenging	I shouldn't have challenged
you shouldn't have challenged
she shouldn't have challenged
we shouldn't have challenged
you shouldn't have challenged
they shouldn't have challenged	I shouldn't have been challenging
you shouldn't have been challenging
she shouldn't have been challenging
we shouldn't have been challenging
you shouldn't have been challenging
they shouldn't have been challenging	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
should I challenge?
should you challenge?
should she challenge?
should we challenge?
should you challenge?
should they challenge? 	should I be challenging?
should you be challenging?
should she be challenging?
should we be challenging?
should you be challenging?
should they be challenging? 	should I have challenged?
should you have challenged?
should she have challenged?
should we have challenged?
should you have challenged?
should they have challenged? 	should I have been challenging?
should you have been challenging?
should she have been challenging?
should we have been challenging?
should you have been challenging?
should they have been challenging? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
shouldn't I challenge?
shouldn't you challenge?
shouldn't she challenge?
shouldn't we challenge?
shouldn't you challenge?
shouldn't they challenge? 	shouldn't I be challenging?
shouldn't you be challenging?
shouldn't she be challenging?
shouldn't we be challenging?
shouldn't you be challenging?
shouldn't they be challenging? 	shouldn't I have challenged?
shouldn't you have challenged?
shouldn't she have challenged?
shouldn't we have challenged?
shouldn't you have challenged?
shouldn't they have challenged? 	shouldn't I have been challenging?
shouldn't you have been challenging?
shouldn't she have been challenging?
shouldn't we have been challenging?
shouldn't you have been challenging?
shouldn't they have been challenging?