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