Conjugación del verbo inglés
MUST STIFF

Verbo regular: stiff - stiffed - stiffed

Afirmación

Forma simple	Forma con V-ing
I must stiff you must stiff she must stiff we must stiff you must stiff they must stiff	I must be stiffing you must be stiffing she must be stiffing we must be stiffing you must be stiffing they must be stiffing
Perfecto	Perfecto con V-ing
I must have stiffed you must have stiffed she must have stiffed we must have stiffed you must have stiffed they must have stiffed	I must have been stiffing you must have been stiffing she must have been stiffing we must have been stiffing you must have been stiffing they must have been stiffing

Negación

Forma simple	Forma con V-ing
I mustn't stiff you mustn't stiff she mustn't stiff we mustn't stiff you mustn't stiff they mustn't stiff	I mustn't be stiffing you mustn't be stiffing she mustn't be stiffing we mustn't be stiffing you mustn't be stiffing they mustn't be stiffing
Perfecto	Perfecto con V-ing
I mustn't have stiffed you mustn't have stiffed she mustn't have stiffed we mustn't have stiffed you mustn't have stiffed they mustn't have stiffed	I mustn't have been stiffing you mustn't have been stiffing she mustn't have been stiffing we mustn't have been stiffing you mustn't have been stiffing they mustn't have been stiffing

Forma interrogativa

Forma simple	Forma con V-ing
must I stiff? must you stiff? must she stiff? must we stiff? must you stiff? must they stiff?	must I be stiffing? must you be stiffing? must she be stiffing? must we be stiffing? must you be stiffing? must they be stiffing?
Perfecto	Perfecto con V-ing
must I have stiffed? must you have stiffed? must she have stiffed? must we have stiffed? must you have stiffed? must they have stiffed?	must I have been stiffing? must you have been stiffing? must she have been stiffing? must we have been stiffing? must you have been stiffing? must they have been stiffing?

Forma interro-negativa

Forma simple	Forma con V-ing
mustn't I stiff? mustn't you stiff? mustn't she stiff? mustn't we stiff? mustn't you stiff? mustn't they stiff?	mustn't I be stiffing? mustn't you be stiffing? mustn't she be stiffing? mustn't we be stiffing? mustn't you be stiffing? mustn't they be stiffing?
Perfecto	Perfecto con V-ing
mustn't I have stiffed? mustn't you have stiffed? mustn't she have stiffed? mustn't we have stiffed? mustn't you have stiffed? mustn't they have stiffed?	mustn't I have been stiffing? mustn't you have been stiffing? mustn't she have been stiffing? mustn't we have been stiffing? mustn't you have been stiffing? mustn't they have been stiffing?