must purl
Regular verb: purl - purled- purled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must purl
you must purl
he must purl
we must purl
you must purl
they must purl 	I must be purling
you must be purling
he must be purling
we must be purling
you must be purling
they must be purling	I must have purled
you must have purled
he must have purled
we must have purled
you must have purled
they must have purled	I must have been purling
you must have been purling
he must have been purling
we must have been purling
you must have been purling
they must have been purling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't purl
you mustn't purl
he mustn't purl
we mustn't purl
you mustn't purl
they mustn't purl 	I mustn't be purling
you mustn't be purling
he mustn't be purling
we mustn't be purling
you mustn't be purling
they mustn't be purling	I mustn't have purled
you mustn't have purled
he mustn't have purled
we mustn't have purled
you mustn't have purled
they mustn't have purled	I mustn't have been purling
you mustn't have been purling
he mustn't have been purling
we mustn't have been purling
you mustn't have been purling
they mustn't have been purling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I purl?
must you purl?
must he purl?
must we purl?
must you purl?
must they purl? 	must I be purling?
must you be purling?
must he be purling?
must we be purling?
must you be purling?
must they be purling? 	must I have purled?
must you have purled?
must he have purled?
must we have purled?
must you have purled?
must they have purled? 	must I have been purling?
must you have been purling?
must he have been purling?
must we have been purling?
must you have been purling?
must they have been purling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I purl?
mustn't you purl?
mustn't he purl?
mustn't we purl?
mustn't you purl?
mustn't they purl? 	mustn't I be purling?
mustn't you be purling?
mustn't he be purling?
mustn't we be purling?
mustn't you be purling?
mustn't they be purling? 	mustn't I have purled?
mustn't you have purled?
mustn't he have purled?
mustn't we have purled?
mustn't you have purled?
mustn't they have purled? 	mustn't I have been purling?
mustn't you have been purling?
mustn't he have been purling?
mustn't we have been purling?
mustn't you have been purling?
mustn't they have been purling?