I must stir you must stir he must stir we must stir you must stir they must stir
V-ing form
I must be stirring you must be stirring he must be stirring we must be stirring you must be stirring they must be stirring
Perfect
I must have stirred you must have stirred he must have stirred we must have stirred you must have stirred they must have stirred
V-ing perfect
I must have been stirring you must have been stirring he must have been stirring we must have been stirring you must have been stirring they must have been stirring
Negation
Simple form
I must not stir you must not stir he must not stir we must not stir you must not stir they must not stir
V-ing form
I must not be stirring you must not be stirring he must not be stirring we must not be stirring you must not be stirring they must not be stirring
Perfect
I must not have stirred you must not have stirred he must not have stirred we must not have stirred you must not have stirred they must not have stirred
V-ing perfect
I must not have been stirring you must not have been stirring he must not have been stirring we must not have been stirring you must not have been stirring they must not have been stirring
Interrogative form
Simple form
must I stir? must you stir? must he stir? must we stir? must you stir? must they stir?
V-ing form
must I be stirring? must you be stirring? must he be stirring? must we be stirring? must you be stirring? must they be stirring?
Perfect
must I have stirred? must you have stirred? must he have stirred? must we have stirred? must you have stirred? must they have stirred?
V-ing perfect
must I have been stirring? must you have been stirring? must he have been stirring? must we have been stirring? must you have been stirring? must they have been stirring?
Interro-negative form
Simple form
must I not stir? must you not stir? must he not stir? must we not stir? must you not stir? must they not stir?
V-ing form
must I not be stirring? must you not be stirring? must he not be stirring? must we not be stirring? must you not be stirring? must they not be stirring?
Perfect
must I not have stirred? must you not have stirred? must he not have stirred? must we not have stirred? must you not have stirred? must they not have stirred?
V-ing perfect
must I not have been stirring? must you not have been stirring? must he not have been stirring? must we not have been stirring? must you not have been stirring? must they not have been stirring?