I must snowboard you must snowboard she must snowboard we must snowboard you must snowboard they must snowboard
V-ing form
I must be snowboarding you must be snowboarding she must be snowboarding we must be snowboarding you must be snowboarding they must be snowboarding
Perfect
I must have snowboarded you must have snowboarded she must have snowboarded we must have snowboarded you must have snowboarded they must have snowboarded
V-ing perfect
I must have been snowboarding you must have been snowboarding she must have been snowboarding we must have been snowboarding you must have been snowboarding they must have been snowboarding
Negation
Simple form
I must not snowboard you must not snowboard she must not snowboard we must not snowboard you must not snowboard they must not snowboard
V-ing form
I must not be snowboarding you must not be snowboarding she must not be snowboarding we must not be snowboarding you must not be snowboarding they must not be snowboarding
Perfect
I must not have snowboarded you must not have snowboarded she must not have snowboarded we must not have snowboarded you must not have snowboarded they must not have snowboarded
V-ing perfect
I must not have been snowboarding you must not have been snowboarding she must not have been snowboarding we must not have been snowboarding you must not have been snowboarding they must not have been snowboarding
Interrogative form
Simple form
must I snowboard? must you snowboard? must she snowboard? must we snowboard? must you snowboard? must they snowboard?
V-ing form
must I be snowboarding? must you be snowboarding? must she be snowboarding? must we be snowboarding? must you be snowboarding? must they be snowboarding?
Perfect
must I have snowboarded? must you have snowboarded? must she have snowboarded? must we have snowboarded? must you have snowboarded? must they have snowboarded?
V-ing perfect
must I have been snowboarding? must you have been snowboarding? must she have been snowboarding? must we have been snowboarding? must you have been snowboarding? must they have been snowboarding?
Interro-negative form
Simple form
must I not snowboard? must you not snowboard? must she not snowboard? must we not snowboard? must you not snowboard? must they not snowboard?
V-ing form
must I not be snowboarding? must you not be snowboarding? must she not be snowboarding? must we not be snowboarding? must you not be snowboarding? must they not be snowboarding?
Perfect
must I not have snowboarded? must you not have snowboarded? must she not have snowboarded? must we not have snowboarded? must you not have snowboarded? must they not have snowboarded?
V-ing perfect
must I not have been snowboarding? must you not have been snowboarding? must she not have been snowboarding? must we not have been snowboarding? must you not have been snowboarding? must they not have been snowboarding?