must forewarn
Regular verb: forewarn - forewarned- forewarned

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must forewarn
you must forewarn
he must forewarn
we must forewarn
you must forewarn
they must forewarn 	I must be forewarning
you must be forewarning
he must be forewarning
we must be forewarning
you must be forewarning
they must be forewarning	I must have forewarned
you must have forewarned
he must have forewarned
we must have forewarned
you must have forewarned
they must have forewarned	I must have been forewarning
you must have been forewarning
he must have been forewarning
we must have been forewarning
you must have been forewarning
they must have been forewarning	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't forewarn
you mustn't forewarn
he mustn't forewarn
we mustn't forewarn
you mustn't forewarn
they mustn't forewarn 	I mustn't be forewarning
you mustn't be forewarning
he mustn't be forewarning
we mustn't be forewarning
you mustn't be forewarning
they mustn't be forewarning	I mustn't have forewarned
you mustn't have forewarned
he mustn't have forewarned
we mustn't have forewarned
you mustn't have forewarned
they mustn't have forewarned	I mustn't have been forewarning
you mustn't have been forewarning
he mustn't have been forewarning
we mustn't have been forewarning
you mustn't have been forewarning
they mustn't have been forewarning	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I forewarn?
must you forewarn?
must he forewarn?
must we forewarn?
must you forewarn?
must they forewarn? 	must I be forewarning?
must you be forewarning?
must he be forewarning?
must we be forewarning?
must you be forewarning?
must they be forewarning? 	must I have forewarned?
must you have forewarned?
must he have forewarned?
must we have forewarned?
must you have forewarned?
must they have forewarned? 	must I have been forewarning?
must you have been forewarning?
must he have been forewarning?
must we have been forewarning?
must you have been forewarning?
must they have been forewarning? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I forewarn?
mustn't you forewarn?
mustn't he forewarn?
mustn't we forewarn?
mustn't you forewarn?
mustn't they forewarn? 	mustn't I be forewarning?
mustn't you be forewarning?
mustn't he be forewarning?
mustn't we be forewarning?
mustn't you be forewarning?
mustn't they be forewarning? 	mustn't I have forewarned?
mustn't you have forewarned?
mustn't he have forewarned?
mustn't we have forewarned?
mustn't you have forewarned?
mustn't they have forewarned? 	mustn't I have been forewarning?
mustn't you have been forewarning?
mustn't he have been forewarning?
mustn't we have been forewarning?
mustn't you have been forewarning?
mustn't they have been forewarning?