Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I must stain sth you must stain sth he must stain sth we must stain sth you must stain sth they must stain sth
V-ing form
I must be stain sthing you must be stain sthing he must be stain sthing we must be stain sthing you must be stain sthing they must be stain sthing
Perfect
I must have stain sthed you must have stain sthed he must have stain sthed we must have stain sthed you must have stain sthed they must have stain sthed
V-ing perfect
I must have been stain sthing you must have been stain sthing he must have been stain sthing we must have been stain sthing you must have been stain sthing they must have been stain sthing
Negation
Simple form
I mustn't stain sth you mustn't stain sth he mustn't stain sth we mustn't stain sth you mustn't stain sth they mustn't stain sth
V-ing form
I mustn't be stain sthing you mustn't be stain sthing he mustn't be stain sthing we mustn't be stain sthing you mustn't be stain sthing they mustn't be stain sthing
Perfect
I mustn't have stain sthed you mustn't have stain sthed he mustn't have stain sthed we mustn't have stain sthed you mustn't have stain sthed they mustn't have stain sthed
V-ing perfect
I mustn't have been stain sthing you mustn't have been stain sthing he mustn't have been stain sthing we mustn't have been stain sthing you mustn't have been stain sthing they mustn't have been stain sthing
Interrogative form
Simple form
must I stain sth? must you stain sth? must he stain sth? must we stain sth? must you stain sth? must they stain sth?
V-ing form
must I be stain sthing? must you be stain sthing? must he be stain sthing? must we be stain sthing? must you be stain sthing? must they be stain sthing?
Perfect
must I have stain sthed? must you have stain sthed? must he have stain sthed? must we have stain sthed? must you have stain sthed? must they have stain sthed?
V-ing perfect
must I have been stain sthing? must you have been stain sthing? must he have been stain sthing? must we have been stain sthing? must you have been stain sthing? must they have been stain sthing?
Interro-negative form
Simple form
mustn't I stain sth? mustn't you stain sth? mustn't he stain sth? mustn't we stain sth? mustn't you stain sth? mustn't they stain sth?
V-ing form
mustn't I be stain sthing? mustn't you be stain sthing? mustn't he be stain sthing? mustn't we be stain sthing? mustn't you be stain sthing? mustn't they be stain sthing?
Perfect
mustn't I have stain sthed? mustn't you have stain sthed? mustn't he have stain sthed? mustn't we have stain sthed? mustn't you have stain sthed? mustn't they have stain sthed?
V-ing perfect
mustn't I have been stain sthing? mustn't you have been stain sthing? mustn't he have been stain sthing? mustn't we have been stain sthing? mustn't you have been stain sthing? mustn't they have been stain sthing?