must silk
Regular verb: silk - silked- silked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must silk
you must silk
he must silk
we must silk
you must silk
they must silk 	I must be silking
you must be silking
he must be silking
we must be silking
you must be silking
they must be silking	I must have silked
you must have silked
he must have silked
we must have silked
you must have silked
they must have silked	I must have been silking
you must have been silking
he must have been silking
we must have been silking
you must have been silking
they must have been silking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't silk
you mustn't silk
he mustn't silk
we mustn't silk
you mustn't silk
they mustn't silk 	I mustn't be silking
you mustn't be silking
he mustn't be silking
we mustn't be silking
you mustn't be silking
they mustn't be silking	I mustn't have silked
you mustn't have silked
he mustn't have silked
we mustn't have silked
you mustn't have silked
they mustn't have silked	I mustn't have been silking
you mustn't have been silking
he mustn't have been silking
we mustn't have been silking
you mustn't have been silking
they mustn't have been silking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I silk?
must you silk?
must he silk?
must we silk?
must you silk?
must they silk? 	must I be silking?
must you be silking?
must he be silking?
must we be silking?
must you be silking?
must they be silking? 	must I have silked?
must you have silked?
must he have silked?
must we have silked?
must you have silked?
must they have silked? 	must I have been silking?
must you have been silking?
must he have been silking?
must we have been silking?
must you have been silking?
must they have been silking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I silk?
mustn't you silk?
mustn't he silk?
mustn't we silk?
mustn't you silk?
mustn't they silk? 	mustn't I be silking?
mustn't you be silking?
mustn't he be silking?
mustn't we be silking?
mustn't you be silking?
mustn't they be silking? 	mustn't I have silked?
mustn't you have silked?
mustn't he have silked?
mustn't we have silked?
mustn't you have silked?
mustn't they have silked? 	mustn't I have been silking?
mustn't you have been silking?
mustn't he have been silking?
mustn't we have been silking?
mustn't you have been silking?
mustn't they have been silking?