must crease
Regular verb: crease - creased- creased

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must crease
you must crease
he must crease
we must crease
you must crease
they must crease 	I must be creasing
you must be creasing
he must be creasing
we must be creasing
you must be creasing
they must be creasing	I must have creased
you must have creased
he must have creased
we must have creased
you must have creased
they must have creased	I must have been creasing
you must have been creasing
he must have been creasing
we must have been creasing
you must have been creasing
they must have been creasing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't crease
you mustn't crease
he mustn't crease
we mustn't crease
you mustn't crease
they mustn't crease 	I mustn't be creasing
you mustn't be creasing
he mustn't be creasing
we mustn't be creasing
you mustn't be creasing
they mustn't be creasing	I mustn't have creased
you mustn't have creased
he mustn't have creased
we mustn't have creased
you mustn't have creased
they mustn't have creased	I mustn't have been creasing
you mustn't have been creasing
he mustn't have been creasing
we mustn't have been creasing
you mustn't have been creasing
they mustn't have been creasing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I crease?
must you crease?
must he crease?
must we crease?
must you crease?
must they crease? 	must I be creasing?
must you be creasing?
must he be creasing?
must we be creasing?
must you be creasing?
must they be creasing? 	must I have creased?
must you have creased?
must he have creased?
must we have creased?
must you have creased?
must they have creased? 	must I have been creasing?
must you have been creasing?
must he have been creasing?
must we have been creasing?
must you have been creasing?
must they have been creasing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I crease?
mustn't you crease?
mustn't he crease?
mustn't we crease?
mustn't you crease?
mustn't they crease? 	mustn't I be creasing?
mustn't you be creasing?
mustn't he be creasing?
mustn't we be creasing?
mustn't you be creasing?
mustn't they be creasing? 	mustn't I have creased?
mustn't you have creased?
mustn't he have creased?
mustn't we have creased?
mustn't you have creased?
mustn't they have creased? 	mustn't I have been creasing?
mustn't you have been creasing?
mustn't he have been creasing?
mustn't we have been creasing?
mustn't you have been creasing?
mustn't they have been creasing?