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