must curtain
Regular verb: curtain - curtained- curtained

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must curtain
you must curtain
he must curtain
we must curtain
you must curtain
they must curtain 	I must be curtaining
you must be curtaining
he must be curtaining
we must be curtaining
you must be curtaining
they must be curtaining	I must have curtained
you must have curtained
he must have curtained
we must have curtained
you must have curtained
they must have curtained	I must have been curtaining
you must have been curtaining
he must have been curtaining
we must have been curtaining
you must have been curtaining
they must have been curtaining	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't curtain
you mustn't curtain
he mustn't curtain
we mustn't curtain
you mustn't curtain
they mustn't curtain 	I mustn't be curtaining
you mustn't be curtaining
he mustn't be curtaining
we mustn't be curtaining
you mustn't be curtaining
they mustn't be curtaining	I mustn't have curtained
you mustn't have curtained
he mustn't have curtained
we mustn't have curtained
you mustn't have curtained
they mustn't have curtained	I mustn't have been curtaining
you mustn't have been curtaining
he mustn't have been curtaining
we mustn't have been curtaining
you mustn't have been curtaining
they mustn't have been curtaining	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I curtain?
must you curtain?
must he curtain?
must we curtain?
must you curtain?
must they curtain? 	must I be curtaining?
must you be curtaining?
must he be curtaining?
must we be curtaining?
must you be curtaining?
must they be curtaining? 	must I have curtained?
must you have curtained?
must he have curtained?
must we have curtained?
must you have curtained?
must they have curtained? 	must I have been curtaining?
must you have been curtaining?
must he have been curtaining?
must we have been curtaining?
must you have been curtaining?
must they have been curtaining? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I curtain?
mustn't you curtain?
mustn't he curtain?
mustn't we curtain?
mustn't you curtain?
mustn't they curtain? 	mustn't I be curtaining?
mustn't you be curtaining?
mustn't he be curtaining?
mustn't we be curtaining?
mustn't you be curtaining?
mustn't they be curtaining? 	mustn't I have curtained?
mustn't you have curtained?
mustn't he have curtained?
mustn't we have curtained?
mustn't you have curtained?
mustn't they have curtained? 	mustn't I have been curtaining?
mustn't you have been curtaining?
mustn't he have been curtaining?
mustn't we have been curtaining?
mustn't you have been curtaining?
mustn't they have been curtaining?