must stab
Regular verb: stab - stabbed- stabbed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must stab
you must stab
he must stab
we must stab
you must stab
they must stab 	I must be stabbing
you must be stabbing
he must be stabbing
we must be stabbing
you must be stabbing
they must be stabbing	I must have stabbed
you must have stabbed
he must have stabbed
we must have stabbed
you must have stabbed
they must have stabbed	I must have been stabbing
you must have been stabbing
he must have been stabbing
we must have been stabbing
you must have been stabbing
they must have been stabbing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't stab
you mustn't stab
he mustn't stab
we mustn't stab
you mustn't stab
they mustn't stab 	I mustn't be stabbing
you mustn't be stabbing
he mustn't be stabbing
we mustn't be stabbing
you mustn't be stabbing
they mustn't be stabbing	I mustn't have stabbed
you mustn't have stabbed
he mustn't have stabbed
we mustn't have stabbed
you mustn't have stabbed
they mustn't have stabbed	I mustn't have been stabbing
you mustn't have been stabbing
he mustn't have been stabbing
we mustn't have been stabbing
you mustn't have been stabbing
they mustn't have been stabbing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I stab?
must you stab?
must he stab?
must we stab?
must you stab?
must they stab? 	must I be stabbing?
must you be stabbing?
must he be stabbing?
must we be stabbing?
must you be stabbing?
must they be stabbing? 	must I have stabbed?
must you have stabbed?
must he have stabbed?
must we have stabbed?
must you have stabbed?
must they have stabbed? 	must I have been stabbing?
must you have been stabbing?
must he have been stabbing?
must we have been stabbing?
must you have been stabbing?
must they have been stabbing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I stab?
mustn't you stab?
mustn't he stab?
mustn't we stab?
mustn't you stab?
mustn't they stab? 	mustn't I be stabbing?
mustn't you be stabbing?
mustn't he be stabbing?
mustn't we be stabbing?
mustn't you be stabbing?
mustn't they be stabbing? 	mustn't I have stabbed?
mustn't you have stabbed?
mustn't he have stabbed?
mustn't we have stabbed?
mustn't you have stabbed?
mustn't they have stabbed? 	mustn't I have been stabbing?
mustn't you have been stabbing?
mustn't he have been stabbing?
mustn't we have been stabbing?
mustn't you have been stabbing?
mustn't they have been stabbing?