must counterfeit
Regular verb: counterfeit - counterfeited- counterfeited

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must counterfeit
you must counterfeit
she must counterfeit
we must counterfeit
you must counterfeit
they must counterfeit 	I must be counterfeiting
you must be counterfeiting
she must be counterfeiting
we must be counterfeiting
you must be counterfeiting
they must be counterfeiting	I must have counterfeited
you must have counterfeited
she must have counterfeited
we must have counterfeited
you must have counterfeited
they must have counterfeited	I must have been counterfeiting
you must have been counterfeiting
she must have been counterfeiting
we must have been counterfeiting
you must have been counterfeiting
they must have been counterfeiting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't counterfeit
you mustn't counterfeit
she mustn't counterfeit
we mustn't counterfeit
you mustn't counterfeit
they mustn't counterfeit 	I mustn't be counterfeiting
you mustn't be counterfeiting
she mustn't be counterfeiting
we mustn't be counterfeiting
you mustn't be counterfeiting
they mustn't be counterfeiting	I mustn't have counterfeited
you mustn't have counterfeited
she mustn't have counterfeited
we mustn't have counterfeited
you mustn't have counterfeited
they mustn't have counterfeited	I mustn't have been counterfeiting
you mustn't have been counterfeiting
she mustn't have been counterfeiting
we mustn't have been counterfeiting
you mustn't have been counterfeiting
they mustn't have been counterfeiting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I counterfeit?
must you counterfeit?
must she counterfeit?
must we counterfeit?
must you counterfeit?
must they counterfeit? 	must I be counterfeiting?
must you be counterfeiting?
must she be counterfeiting?
must we be counterfeiting?
must you be counterfeiting?
must they be counterfeiting? 	must I have counterfeited?
must you have counterfeited?
must she have counterfeited?
must we have counterfeited?
must you have counterfeited?
must they have counterfeited? 	must I have been counterfeiting?
must you have been counterfeiting?
must she have been counterfeiting?
must we have been counterfeiting?
must you have been counterfeiting?
must they have been counterfeiting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I counterfeit?
mustn't you counterfeit?
mustn't she counterfeit?
mustn't we counterfeit?
mustn't you counterfeit?
mustn't they counterfeit? 	mustn't I be counterfeiting?
mustn't you be counterfeiting?
mustn't she be counterfeiting?
mustn't we be counterfeiting?
mustn't you be counterfeiting?
mustn't they be counterfeiting? 	mustn't I have counterfeited?
mustn't you have counterfeited?
mustn't she have counterfeited?
mustn't we have counterfeited?
mustn't you have counterfeited?
mustn't they have counterfeited? 	mustn't I have been counterfeiting?
mustn't you have been counterfeiting?
mustn't she have been counterfeiting?
mustn't we have been counterfeiting?
mustn't you have been counterfeiting?
mustn't they have been counterfeiting?