I must engage you must engage he must engage we must engage you must engage they must engage
V-ing form
I must be engaging you must be engaging he must be engaging we must be engaging you must be engaging they must be engaging
Perfect
I must have engaged you must have engaged he must have engaged we must have engaged you must have engaged they must have engaged
V-ing perfect
I must have been engaging you must have been engaging he must have been engaging we must have been engaging you must have been engaging they must have been engaging
Negation
Simple form
I must not engage you must not engage he must not engage we must not engage you must not engage they must not engage
V-ing form
I must not be engaging you must not be engaging he must not be engaging we must not be engaging you must not be engaging they must not be engaging
Perfect
I must not have engaged you must not have engaged he must not have engaged we must not have engaged you must not have engaged they must not have engaged
V-ing perfect
I must not have been engaging you must not have been engaging he must not have been engaging we must not have been engaging you must not have been engaging they must not have been engaging
Interrogative form
Simple form
must I engage? must you engage? must he engage? must we engage? must you engage? must they engage?
V-ing form
must I be engaging? must you be engaging? must he be engaging? must we be engaging? must you be engaging? must they be engaging?
Perfect
must I have engaged? must you have engaged? must he have engaged? must we have engaged? must you have engaged? must they have engaged?
V-ing perfect
must I have been engaging? must you have been engaging? must he have been engaging? must we have been engaging? must you have been engaging? must they have been engaging?
Interro-negative form
Simple form
must I not engage? must you not engage? must he not engage? must we not engage? must you not engage? must they not engage?
V-ing form
must I not be engaging? must you not be engaging? must he not be engaging? must we not be engaging? must you not be engaging? must they not be engaging?
Perfect
must I not have engaged? must you not have engaged? must he not have engaged? must we not have engaged? must you not have engaged? must they not have engaged?
V-ing perfect
must I not have been engaging? must you not have been engaging? must he not have been engaging? must we not have been engaging? must you not have been engaging? must they not have been engaging?