should fail
Verbo regular: fail - failed- failed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I'd fail
you'd fail
she'd fail
we'd fail
you'd fail
they'd fail 	I'd be failing
you'd be failing
she'd be failing
we'd be failing
you'd be failing
they'd be failing	I should've failed
you should've failed
she should've failed
we should've failed
you should've failed
they should've failed	I should've been failing
you should've been failing
she should've been failing
we should've been failing
you should've been failing
they should've been failing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I shouldn't fail
you shouldn't fail
she shouldn't fail
we shouldn't fail
you shouldn't fail
they shouldn't fail 	I shouldn't be failing
you shouldn't be failing
she shouldn't be failing
we shouldn't be failing
you shouldn't be failing
they shouldn't be failing	I shouldn't have failed
you shouldn't have failed
she shouldn't have failed
we shouldn't have failed
you shouldn't have failed
they shouldn't have failed	I shouldn't have been failing
you shouldn't have been failing
she shouldn't have been failing
we shouldn't have been failing
you shouldn't have been failing
they shouldn't have been failing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
should I fail?
should you fail?
should she fail?
should we fail?
should you fail?
should they fail? 	should I be failing?
should you be failing?
should she be failing?
should we be failing?
should you be failing?
should they be failing? 	should I have failed?
should you have failed?
should she have failed?
should we have failed?
should you have failed?
should they have failed? 	should I have been failing?
should you have been failing?
should she have been failing?
should we have been failing?
should you have been failing?
should they have been failing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
shouldn't I fail?
shouldn't you fail?
shouldn't she fail?
shouldn't we fail?
shouldn't you fail?
shouldn't they fail? 	shouldn't I be failing?
shouldn't you be failing?
shouldn't she be failing?
shouldn't we be failing?
shouldn't you be failing?
shouldn't they be failing? 	shouldn't I have failed?
shouldn't you have failed?
shouldn't she have failed?
shouldn't we have failed?
shouldn't you have failed?
shouldn't they have failed? 	shouldn't I have been failing?
shouldn't you have been failing?
shouldn't she have been failing?
shouldn't we have been failing?
shouldn't you have been failing?
shouldn't they have been failing?