must sneak
Irregular verb: sneak - sneaked, snuck- snuck

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must sneak
you must sneak
he must sneak
we must sneak
you must sneak
they must sneak 	I must be sneaking
you must be sneaking
he must be sneaking
we must be sneaking
you must be sneaking
they must be sneaking	I must have snuck
you must have snuck
he must have snuck
we must have snuck
you must have snuck
they must have snuck	I must have been sneaking
you must have been sneaking
he must have been sneaking
we must have been sneaking
you must have been sneaking
they must have been sneaking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't sneak
you mustn't sneak
he mustn't sneak
we mustn't sneak
you mustn't sneak
they mustn't sneak 	I mustn't be sneaking
you mustn't be sneaking
he mustn't be sneaking
we mustn't be sneaking
you mustn't be sneaking
they mustn't be sneaking	I mustn't have snuck
you mustn't have snuck
he mustn't have snuck
we mustn't have snuck
you mustn't have snuck
they mustn't have snuck	I mustn't have been sneaking
you mustn't have been sneaking
he mustn't have been sneaking
we mustn't have been sneaking
you mustn't have been sneaking
they mustn't have been sneaking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I sneak?
must you sneak?
must he sneak?
must we sneak?
must you sneak?
must they sneak? 	must I be sneaking?
must you be sneaking?
must he be sneaking?
must we be sneaking?
must you be sneaking?
must they be sneaking? 	must I have snuck?
must you have snuck?
must he have snuck?
must we have snuck?
must you have snuck?
must they have snuck? 	must I have been sneaking?
must you have been sneaking?
must he have been sneaking?
must we have been sneaking?
must you have been sneaking?
must they have been sneaking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I sneak?
mustn't you sneak?
mustn't he sneak?
mustn't we sneak?
mustn't you sneak?
mustn't they sneak? 	mustn't I be sneaking?
mustn't you be sneaking?
mustn't he be sneaking?
mustn't we be sneaking?
mustn't you be sneaking?
mustn't they be sneaking? 	mustn't I have snuck?
mustn't you have snuck?
mustn't he have snuck?
mustn't we have snuck?
mustn't you have snuck?
mustn't they have snuck? 	mustn't I have been sneaking?
mustn't you have been sneaking?
mustn't he have been sneaking?
mustn't we have been sneaking?
mustn't you have been sneaking?
mustn't they have been sneaking?