I must snuff you must snuff she must snuff we must snuff you must snuff they must snuff
V-ing form
I must be snuffing you must be snuffing she must be snuffing we must be snuffing you must be snuffing they must be snuffing
Perfect
I must have snuffed you must have snuffed she must have snuffed we must have snuffed you must have snuffed they must have snuffed
V-ing perfect
I must have been snuffing you must have been snuffing she must have been snuffing we must have been snuffing you must have been snuffing they must have been snuffing
Negation
Simple form
I must not snuff you must not snuff she must not snuff we must not snuff you must not snuff they must not snuff
V-ing form
I must not be snuffing you must not be snuffing she must not be snuffing we must not be snuffing you must not be snuffing they must not be snuffing
Perfect
I must not have snuffed you must not have snuffed she must not have snuffed we must not have snuffed you must not have snuffed they must not have snuffed
V-ing perfect
I must not have been snuffing you must not have been snuffing she must not have been snuffing we must not have been snuffing you must not have been snuffing they must not have been snuffing
Interrogative form
Simple form
must I snuff? must you snuff? must she snuff? must we snuff? must you snuff? must they snuff?
V-ing form
must I be snuffing? must you be snuffing? must she be snuffing? must we be snuffing? must you be snuffing? must they be snuffing?
Perfect
must I have snuffed? must you have snuffed? must she have snuffed? must we have snuffed? must you have snuffed? must they have snuffed?
V-ing perfect
must I have been snuffing? must you have been snuffing? must she have been snuffing? must we have been snuffing? must you have been snuffing? must they have been snuffing?
Interro-negative form
Simple form
must I not snuff? must you not snuff? must she not snuff? must we not snuff? must you not snuff? must they not snuff?
V-ing form
must I not be snuffing? must you not be snuffing? must she not be snuffing? must we not be snuffing? must you not be snuffing? must they not be snuffing?
Perfect
must I not have snuffed? must you not have snuffed? must she not have snuffed? must we not have snuffed? must you not have snuffed? must they not have snuffed?
V-ing perfect
must I not have been snuffing? must you not have been snuffing? must she not have been snuffing? must we not have been snuffing? must you not have been snuffing? must they not have been snuffing?