I must bark you must bark he must bark we must bark you must bark they must bark
V-ing form
I must be barking you must be barking he must be barking we must be barking you must be barking they must be barking
Perfect
I must have barked you must have barked he must have barked we must have barked you must have barked they must have barked
V-ing perfect
I must have been barking you must have been barking he must have been barking we must have been barking you must have been barking they must have been barking
Negation
Simple form
I mustn't bark you mustn't bark he mustn't bark we mustn't bark you mustn't bark they mustn't bark
V-ing form
I mustn't be barking you mustn't be barking he mustn't be barking we mustn't be barking you mustn't be barking they mustn't be barking
Perfect
I mustn't have barked you mustn't have barked he mustn't have barked we mustn't have barked you mustn't have barked they mustn't have barked
V-ing perfect
I mustn't have been barking you mustn't have been barking he mustn't have been barking we mustn't have been barking you mustn't have been barking they mustn't have been barking
Interrogative form
Simple form
must I bark? must you bark? must he bark? must we bark? must you bark? must they bark?
V-ing form
must I be barking? must you be barking? must he be barking? must we be barking? must you be barking? must they be barking?
Perfect
must I have barked? must you have barked? must he have barked? must we have barked? must you have barked? must they have barked?
V-ing perfect
must I have been barking? must you have been barking? must he have been barking? must we have been barking? must you have been barking? must they have been barking?
Interro-negative form
Simple form
mustn't I bark? mustn't you bark? mustn't he bark? mustn't we bark? mustn't you bark? mustn't they bark?
V-ing form
mustn't I be barking? mustn't you be barking? mustn't he be barking? mustn't we be barking? mustn't you be barking? mustn't they be barking?
Perfect
mustn't I have barked? mustn't you have barked? mustn't he have barked? mustn't we have barked? mustn't you have barked? mustn't they have barked?
V-ing perfect
mustn't I have been barking? mustn't you have been barking? mustn't he have been barking? mustn't we have been barking? mustn't you have been barking? mustn't they have been barking?