must trill
Regular verb: trill - trilled- trilled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must trill
you must trill
he must trill
we must trill
you must trill
they must trill 	I must be trilling
you must be trilling
he must be trilling
we must be trilling
you must be trilling
they must be trilling	I must have trilled
you must have trilled
he must have trilled
we must have trilled
you must have trilled
they must have trilled	I must have been trilling
you must have been trilling
he must have been trilling
we must have been trilling
you must have been trilling
they must have been trilling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't trill
you mustn't trill
he mustn't trill
we mustn't trill
you mustn't trill
they mustn't trill 	I mustn't be trilling
you mustn't be trilling
he mustn't be trilling
we mustn't be trilling
you mustn't be trilling
they mustn't be trilling	I mustn't have trilled
you mustn't have trilled
he mustn't have trilled
we mustn't have trilled
you mustn't have trilled
they mustn't have trilled	I mustn't have been trilling
you mustn't have been trilling
he mustn't have been trilling
we mustn't have been trilling
you mustn't have been trilling
they mustn't have been trilling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I trill?
must you trill?
must he trill?
must we trill?
must you trill?
must they trill? 	must I be trilling?
must you be trilling?
must he be trilling?
must we be trilling?
must you be trilling?
must they be trilling? 	must I have trilled?
must you have trilled?
must he have trilled?
must we have trilled?
must you have trilled?
must they have trilled? 	must I have been trilling?
must you have been trilling?
must he have been trilling?
must we have been trilling?
must you have been trilling?
must they have been trilling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I trill?
mustn't you trill?
mustn't he trill?
mustn't we trill?
mustn't you trill?
mustn't they trill? 	mustn't I be trilling?
mustn't you be trilling?
mustn't he be trilling?
mustn't we be trilling?
mustn't you be trilling?
mustn't they be trilling? 	mustn't I have trilled?
mustn't you have trilled?
mustn't he have trilled?
mustn't we have trilled?
mustn't you have trilled?
mustn't they have trilled? 	mustn't I have been trilling?
mustn't you have been trilling?
mustn't he have been trilling?
mustn't we have been trilling?
mustn't you have been trilling?
mustn't they have been trilling?