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 must not bark you must not bark he must not bark we must not bark you must not bark they must not bark
V-ing form
I must not be barking you must not be barking he must not be barking we must not be barking you must not be barking they must not be barking
Perfect
I must not have barked you must not have barked he must not have barked we must not have barked you must not have barked they must not have barked
V-ing perfect
I must not have been barking you must not have been barking he must not have been barking we must not have been barking you must not have been barking they must not 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
must I not bark? must you not bark? must he not bark? must we not bark? must you not bark? must they not bark?
V-ing form
must I not be barking? must you not be barking? must he not be barking? must we not be barking? must you not be barking? must they not be barking?
Perfect
must I not have barked? must you not have barked? must he not have barked? must we not have barked? must you not have barked? must they not have barked?
V-ing perfect
must I not have been barking? must you not have been barking? must he not have been barking? must we not have been barking? must you not have been barking? must they not have been barking?