must prewarn
Regular verb: prewarn - prewarned- prewarned

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

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

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

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