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