must answer
Verbo regular: answer - answered- answered

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must answer
you must answer
she must answer
we must answer
you must answer
they must answer 	I must be answering
you must be answering
she must be answering
we must be answering
you must be answering
they must be answering	I must have answered
you must have answered
she must have answered
we must have answered
you must have answered
they must have answered	I must have been answering
you must have been answering
she must have been answering
we must have been answering
you must have been answering
they must have been answering	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I mustn't answer
you mustn't answer
she mustn't answer
we mustn't answer
you mustn't answer
they mustn't answer 	I mustn't be answering
you mustn't be answering
she mustn't be answering
we mustn't be answering
you mustn't be answering
they mustn't be answering	I mustn't have answered
you mustn't have answered
she mustn't have answered
we mustn't have answered
you mustn't have answered
they mustn't have answered	I mustn't have been answering
you mustn't have been answering
she mustn't have been answering
we mustn't have been answering
you mustn't have been answering
they mustn't have been answering	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I answer?
must you answer?
must she answer?
must we answer?
must you answer?
must they answer? 	must I be answering?
must you be answering?
must she be answering?
must we be answering?
must you be answering?
must they be answering? 	must I have answered?
must you have answered?
must she have answered?
must we have answered?
must you have answered?
must they have answered? 	must I have been answering?
must you have been answering?
must she have been answering?
must we have been answering?
must you have been answering?
must they have been answering? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
mustn't I answer?
mustn't you answer?
mustn't she answer?
mustn't we answer?
mustn't you answer?
mustn't they answer? 	mustn't I be answering?
mustn't you be answering?
mustn't she be answering?
mustn't we be answering?
mustn't you be answering?
mustn't they be answering? 	mustn't I have answered?
mustn't you have answered?
mustn't she have answered?
mustn't we have answered?
mustn't you have answered?
mustn't they have answered? 	mustn't I have been answering?
mustn't you have been answering?
mustn't she have been answering?
mustn't we have been answering?
mustn't you have been answering?
mustn't they have been answering?