must tough
Verbo regular: tough - toughed- toughed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must tough
you must tough
she must tough
we must tough
you must tough
they must tough 	I must be toughing
you must be toughing
she must be toughing
we must be toughing
you must be toughing
they must be toughing	I must have toughed
you must have toughed
she must have toughed
we must have toughed
you must have toughed
they must have toughed	I must have been toughing
you must have been toughing
she must have been toughing
we must have been toughing
you must have been toughing
they must have been toughing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I mustn't tough
you mustn't tough
she mustn't tough
we mustn't tough
you mustn't tough
they mustn't tough 	I mustn't be toughing
you mustn't be toughing
she mustn't be toughing
we mustn't be toughing
you mustn't be toughing
they mustn't be toughing	I mustn't have toughed
you mustn't have toughed
she mustn't have toughed
we mustn't have toughed
you mustn't have toughed
they mustn't have toughed	I mustn't have been toughing
you mustn't have been toughing
she mustn't have been toughing
we mustn't have been toughing
you mustn't have been toughing
they mustn't have been toughing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I tough?
must you tough?
must she tough?
must we tough?
must you tough?
must they tough? 	must I be toughing?
must you be toughing?
must she be toughing?
must we be toughing?
must you be toughing?
must they be toughing? 	must I have toughed?
must you have toughed?
must she have toughed?
must we have toughed?
must you have toughed?
must they have toughed? 	must I have been toughing?
must you have been toughing?
must she have been toughing?
must we have been toughing?
must you have been toughing?
must they have been toughing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
mustn't I tough?
mustn't you tough?
mustn't she tough?
mustn't we tough?
mustn't you tough?
mustn't they tough? 	mustn't I be toughing?
mustn't you be toughing?
mustn't she be toughing?
mustn't we be toughing?
mustn't you be toughing?
mustn't they be toughing? 	mustn't I have toughed?
mustn't you have toughed?
mustn't she have toughed?
mustn't we have toughed?
mustn't you have toughed?
mustn't they have toughed? 	mustn't I have been toughing?
mustn't you have been toughing?
mustn't she have been toughing?
mustn't we have been toughing?
mustn't you have been toughing?
mustn't they have been toughing?