must discuss
Regular verb: discuss - discussed- discussed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must discuss
you must discuss
he must discuss
we must discuss
you must discuss
they must discuss 	I must be discussing
you must be discussing
he must be discussing
we must be discussing
you must be discussing
they must be discussing	I must have discussed
you must have discussed
he must have discussed
we must have discussed
you must have discussed
they must have discussed	I must have been discussing
you must have been discussing
he must have been discussing
we must have been discussing
you must have been discussing
they must have been discussing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't discuss
you mustn't discuss
he mustn't discuss
we mustn't discuss
you mustn't discuss
they mustn't discuss 	I mustn't be discussing
you mustn't be discussing
he mustn't be discussing
we mustn't be discussing
you mustn't be discussing
they mustn't be discussing	I mustn't have discussed
you mustn't have discussed
he mustn't have discussed
we mustn't have discussed
you mustn't have discussed
they mustn't have discussed	I mustn't have been discussing
you mustn't have been discussing
he mustn't have been discussing
we mustn't have been discussing
you mustn't have been discussing
they mustn't have been discussing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I discuss?
must you discuss?
must he discuss?
must we discuss?
must you discuss?
must they discuss? 	must I be discussing?
must you be discussing?
must he be discussing?
must we be discussing?
must you be discussing?
must they be discussing? 	must I have discussed?
must you have discussed?
must he have discussed?
must we have discussed?
must you have discussed?
must they have discussed? 	must I have been discussing?
must you have been discussing?
must he have been discussing?
must we have been discussing?
must you have been discussing?
must they have been discussing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I discuss?
mustn't you discuss?
mustn't he discuss?
mustn't we discuss?
mustn't you discuss?
mustn't they discuss? 	mustn't I be discussing?
mustn't you be discussing?
mustn't he be discussing?
mustn't we be discussing?
mustn't you be discussing?
mustn't they be discussing? 	mustn't I have discussed?
mustn't you have discussed?
mustn't he have discussed?
mustn't we have discussed?
mustn't you have discussed?
mustn't they have discussed? 	mustn't I have been discussing?
mustn't you have been discussing?
mustn't he have been discussing?
mustn't we have been discussing?
mustn't you have been discussing?
mustn't they have been discussing?