must double-tongue
Regular verb: double-tongue - double-tongued- double-tongued

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must double-tongue
you must double-tongue
he must double-tongue
we must double-tongue
you must double-tongue
they must double-tongue 	I must be double-tonguing
you must be double-tonguing
he must be double-tonguing
we must be double-tonguing
you must be double-tonguing
they must be double-tonguing	I must have double-tongued
you must have double-tongued
he must have double-tongued
we must have double-tongued
you must have double-tongued
they must have double-tongued	I must have been double-tonguing
you must have been double-tonguing
he must have been double-tonguing
we must have been double-tonguing
you must have been double-tonguing
they must have been double-tonguing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't double-tongue
you mustn't double-tongue
he mustn't double-tongue
we mustn't double-tongue
you mustn't double-tongue
they mustn't double-tongue 	I mustn't be double-tonguing
you mustn't be double-tonguing
he mustn't be double-tonguing
we mustn't be double-tonguing
you mustn't be double-tonguing
they mustn't be double-tonguing	I mustn't have double-tongued
you mustn't have double-tongued
he mustn't have double-tongued
we mustn't have double-tongued
you mustn't have double-tongued
they mustn't have double-tongued	I mustn't have been double-tonguing
you mustn't have been double-tonguing
he mustn't have been double-tonguing
we mustn't have been double-tonguing
you mustn't have been double-tonguing
they mustn't have been double-tonguing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I double-tongue?
must you double-tongue?
must he double-tongue?
must we double-tongue?
must you double-tongue?
must they double-tongue? 	must I be double-tonguing?
must you be double-tonguing?
must he be double-tonguing?
must we be double-tonguing?
must you be double-tonguing?
must they be double-tonguing? 	must I have double-tongued?
must you have double-tongued?
must he have double-tongued?
must we have double-tongued?
must you have double-tongued?
must they have double-tongued? 	must I have been double-tonguing?
must you have been double-tonguing?
must he have been double-tonguing?
must we have been double-tonguing?
must you have been double-tonguing?
must they have been double-tonguing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I double-tongue?
mustn't you double-tongue?
mustn't he double-tongue?
mustn't we double-tongue?
mustn't you double-tongue?
mustn't they double-tongue? 	mustn't I be double-tonguing?
mustn't you be double-tonguing?
mustn't he be double-tonguing?
mustn't we be double-tonguing?
mustn't you be double-tonguing?
mustn't they be double-tonguing? 	mustn't I have double-tongued?
mustn't you have double-tongued?
mustn't he have double-tongued?
mustn't we have double-tongued?
mustn't you have double-tongued?
mustn't they have double-tongued? 	mustn't I have been double-tonguing?
mustn't you have been double-tonguing?
mustn't he have been double-tonguing?
mustn't we have been double-tonguing?
mustn't you have been double-tonguing?
mustn't they have been double-tonguing?