ought to prewarn
Regular verb: prewarn - prewarned- prewarned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I ought to prewarn
you ought to prewarn
she ought to prewarn
we ought to prewarn
you ought to prewarn
they ought to prewarn 	I ought to be prewarning
you ought to be prewarning
she ought to be prewarning
we ought to be prewarning
you ought to be prewarning
they ought to be prewarning	I ought to have prewarned
you ought to have prewarned
she ought to have prewarned
we ought to have prewarned
you ought to have prewarned
they ought to have prewarned	I ought to have been prewarning
you ought to have been prewarning
she ought to have been prewarning
we ought to have been prewarning
you ought to have been prewarning
they ought to have been prewarning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I oughtn't to prewarn
you oughtn't to prewarn
she oughtn't to prewarn
we oughtn't to prewarn
you oughtn't to prewarn
they oughtn't to prewarn 	I oughtn't to be prewarning
you oughtn't to be prewarning
she oughtn't to be prewarning
we oughtn't to be prewarning
you oughtn't to be prewarning
they oughtn't to be prewarning	I oughtn't to have prewarned
you oughtn't to have prewarned
she oughtn't to have prewarned
we oughtn't to have prewarned
you oughtn't to have prewarned
they oughtn't to have prewarned	I oughtn't to have been prewarning
you oughtn't to have been prewarning
she oughtn't to have been prewarning
we oughtn't to have been prewarning
you oughtn't to have been prewarning
they oughtn't to have been prewarning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
ought to I prewarn?
ought to you prewarn?
ought to she prewarn?
ought to we prewarn?
ought to you prewarn?
ought to they prewarn? 	ought to I be prewarning?
ought to you be prewarning?
ought to she be prewarning?
ought to we be prewarning?
ought to you be prewarning?
ought to they be prewarning? 	ought to I have prewarned?
ought to you have prewarned?
ought to she have prewarned?
ought to we have prewarned?
ought to you have prewarned?
ought to they have prewarned? 	ought to I have been prewarning?
ought to you have been prewarning?
ought to she have been prewarning?
ought to we have been prewarning?
ought to you have been prewarning?
ought to they have been prewarning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
oughtn't I to prewarn?
oughtn't you to prewarn?
oughtn't she to prewarn?
oughtn't we to prewarn?
oughtn't you to prewarn?
oughtn't they to prewarn? 	oughtn't I to be prewarning?
oughtn't you to be prewarning?
oughtn't she to be prewarning?
oughtn't we to be prewarning?
oughtn't you to be prewarning?
oughtn't they to be prewarning? 	oughtn't I to have prewarned?
oughtn't you to have prewarned?
oughtn't she to have prewarned?
oughtn't we to have prewarned?
oughtn't you to have prewarned?
oughtn't they to have prewarned? 	oughtn't I to have been prewarning?
oughtn't you to have been prewarning?
oughtn't she to have been prewarning?
oughtn't we to have been prewarning?
oughtn't you to have been prewarning?
oughtn't they to have been prewarning?