must clack
Verbo regular: clack - clacked- clacked

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must clack
you must clack
he must clack
we must clack
you must clack
they must clack 	I must be clacking
you must be clacking
he must be clacking
we must be clacking
you must be clacking
they must be clacking	I must have clacked
you must have clacked
he must have clacked
we must have clacked
you must have clacked
they must have clacked	I must have been clacking
you must have been clacking
he must have been clacking
we must have been clacking
you must have been clacking
they must have been clacking	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I mustn't clack
you mustn't clack
he mustn't clack
we mustn't clack
you mustn't clack
they mustn't clack 	I mustn't be clacking
you mustn't be clacking
he mustn't be clacking
we mustn't be clacking
you mustn't be clacking
they mustn't be clacking	I mustn't have clacked
you mustn't have clacked
he mustn't have clacked
we mustn't have clacked
you mustn't have clacked
they mustn't have clacked	I mustn't have been clacking
you mustn't have been clacking
he mustn't have been clacking
we mustn't have been clacking
you mustn't have been clacking
they mustn't have been clacking	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I clack?
must you clack?
must he clack?
must we clack?
must you clack?
must they clack? 	must I be clacking?
must you be clacking?
must he be clacking?
must we be clacking?
must you be clacking?
must they be clacking? 	must I have clacked?
must you have clacked?
must he have clacked?
must we have clacked?
must you have clacked?
must they have clacked? 	must I have been clacking?
must you have been clacking?
must he have been clacking?
must we have been clacking?
must you have been clacking?
must they have been clacking? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
mustn't I clack?
mustn't you clack?
mustn't he clack?
mustn't we clack?
mustn't you clack?
mustn't they clack? 	mustn't I be clacking?
mustn't you be clacking?
mustn't he be clacking?
mustn't we be clacking?
mustn't you be clacking?
mustn't they be clacking? 	mustn't I have clacked?
mustn't you have clacked?
mustn't he have clacked?
mustn't we have clacked?
mustn't you have clacked?
mustn't they have clacked? 	mustn't I have been clacking?
mustn't you have been clacking?
mustn't he have been clacking?
mustn't we have been clacking?
mustn't you have been clacking?
mustn't they have been clacking?