must deskill
Regular verb: deskill - deskilled- deskilled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must deskill
you must deskill
he must deskill
we must deskill
you must deskill
they must deskill 	I must be deskilling
you must be deskilling
he must be deskilling
we must be deskilling
you must be deskilling
they must be deskilling	I must have deskilled
you must have deskilled
he must have deskilled
we must have deskilled
you must have deskilled
they must have deskilled	I must have been deskilling
you must have been deskilling
he must have been deskilling
we must have been deskilling
you must have been deskilling
they must have been deskilling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't deskill
you mustn't deskill
he mustn't deskill
we mustn't deskill
you mustn't deskill
they mustn't deskill 	I mustn't be deskilling
you mustn't be deskilling
he mustn't be deskilling
we mustn't be deskilling
you mustn't be deskilling
they mustn't be deskilling	I mustn't have deskilled
you mustn't have deskilled
he mustn't have deskilled
we mustn't have deskilled
you mustn't have deskilled
they mustn't have deskilled	I mustn't have been deskilling
you mustn't have been deskilling
he mustn't have been deskilling
we mustn't have been deskilling
you mustn't have been deskilling
they mustn't have been deskilling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I deskill?
must you deskill?
must he deskill?
must we deskill?
must you deskill?
must they deskill? 	must I be deskilling?
must you be deskilling?
must he be deskilling?
must we be deskilling?
must you be deskilling?
must they be deskilling? 	must I have deskilled?
must you have deskilled?
must he have deskilled?
must we have deskilled?
must you have deskilled?
must they have deskilled? 	must I have been deskilling?
must you have been deskilling?
must he have been deskilling?
must we have been deskilling?
must you have been deskilling?
must they have been deskilling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I deskill?
mustn't you deskill?
mustn't he deskill?
mustn't we deskill?
mustn't you deskill?
mustn't they deskill? 	mustn't I be deskilling?
mustn't you be deskilling?
mustn't he be deskilling?
mustn't we be deskilling?
mustn't you be deskilling?
mustn't they be deskilling? 	mustn't I have deskilled?
mustn't you have deskilled?
mustn't he have deskilled?
mustn't we have deskilled?
mustn't you have deskilled?
mustn't they have deskilled? 	mustn't I have been deskilling?
mustn't you have been deskilling?
mustn't he have been deskilling?
mustn't we have been deskilling?
mustn't you have been deskilling?
mustn't they have been deskilling?