must decipher
Regular verb: decipher - deciphered- deciphered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must decipher
you must decipher
he must decipher
we must decipher
you must decipher
they must decipher 	I must be deciphering
you must be deciphering
he must be deciphering
we must be deciphering
you must be deciphering
they must be deciphering	I must have deciphered
you must have deciphered
he must have deciphered
we must have deciphered
you must have deciphered
they must have deciphered	I must have been deciphering
you must have been deciphering
he must have been deciphering
we must have been deciphering
you must have been deciphering
they must have been deciphering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't decipher
you mustn't decipher
he mustn't decipher
we mustn't decipher
you mustn't decipher
they mustn't decipher 	I mustn't be deciphering
you mustn't be deciphering
he mustn't be deciphering
we mustn't be deciphering
you mustn't be deciphering
they mustn't be deciphering	I mustn't have deciphered
you mustn't have deciphered
he mustn't have deciphered
we mustn't have deciphered
you mustn't have deciphered
they mustn't have deciphered	I mustn't have been deciphering
you mustn't have been deciphering
he mustn't have been deciphering
we mustn't have been deciphering
you mustn't have been deciphering
they mustn't have been deciphering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I decipher?
must you decipher?
must he decipher?
must we decipher?
must you decipher?
must they decipher? 	must I be deciphering?
must you be deciphering?
must he be deciphering?
must we be deciphering?
must you be deciphering?
must they be deciphering? 	must I have deciphered?
must you have deciphered?
must he have deciphered?
must we have deciphered?
must you have deciphered?
must they have deciphered? 	must I have been deciphering?
must you have been deciphering?
must he have been deciphering?
must we have been deciphering?
must you have been deciphering?
must they have been deciphering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I decipher?
mustn't you decipher?
mustn't he decipher?
mustn't we decipher?
mustn't you decipher?
mustn't they decipher? 	mustn't I be deciphering?
mustn't you be deciphering?
mustn't he be deciphering?
mustn't we be deciphering?
mustn't you be deciphering?
mustn't they be deciphering? 	mustn't I have deciphered?
mustn't you have deciphered?
mustn't he have deciphered?
mustn't we have deciphered?
mustn't you have deciphered?
mustn't they have deciphered? 	mustn't I have been deciphering?
mustn't you have been deciphering?
mustn't he have been deciphering?
mustn't we have been deciphering?
mustn't you have been deciphering?
mustn't they have been deciphering?