I must seek you must seek he must seek we must seek you must seek they must seek
V-ing form
I must be seeking you must be seeking he must be seeking we must be seeking you must be seeking they must be seeking
Perfect
I must have sought you must have sought he must have sought we must have sought you must have sought they must have sought
V-ing perfect
I must have been seeking you must have been seeking he must have been seeking we must have been seeking you must have been seeking they must have been seeking
Negation
Simple form
I must not seek you must not seek he must not seek we must not seek you must not seek they must not seek
V-ing form
I must not be seeking you must not be seeking he must not be seeking we must not be seeking you must not be seeking they must not be seeking
Perfect
I must not have sought you must not have sought he must not have sought we must not have sought you must not have sought they must not have sought
V-ing perfect
I must not have been seeking you must not have been seeking he must not have been seeking we must not have been seeking you must not have been seeking they must not have been seeking
Interrogative form
Simple form
must I seek? must you seek? must he seek? must we seek? must you seek? must they seek?
V-ing form
must I be seeking? must you be seeking? must he be seeking? must we be seeking? must you be seeking? must they be seeking?
Perfect
must I have sought? must you have sought? must he have sought? must we have sought? must you have sought? must they have sought?
V-ing perfect
must I have been seeking? must you have been seeking? must he have been seeking? must we have been seeking? must you have been seeking? must they have been seeking?
Interro-negative form
Simple form
must I not seek? must you not seek? must he not seek? must we not seek? must you not seek? must they not seek?
V-ing form
must I not be seeking? must you not be seeking? must he not be seeking? must we not be seeking? must you not be seeking? must they not be seeking?
Perfect
must I not have sought? must you not have sought? must he not have sought? must we not have sought? must you not have sought? must they not have sought?
V-ing perfect
must I not have been seeking? must you not have been seeking? must he not have been seeking? must we not have been seeking? must you not have been seeking? must they not have been seeking?