Conjugación del verbo inglés
MUST STIFF

Verbo regular: stiff - stiffed - stiffed

Afirmación

Forma simple	Forma con V-ing
I must stiff you must stiff he must stiff we must stiff you must stiff they must stiff	I must be stiffing you must be stiffing he 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 he 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 he 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 must not stiff you must not stiff he must not stiff we must not stiff you must not stiff they must not stiff	I must not be stiffing you must not be stiffing he must not be stiffing we must not be stiffing you must not be stiffing they must not be stiffing
Perfecto	Perfecto con V-ing
I must not have stiffed you must not have stiffed he must not have stiffed we must not have stiffed you must not have stiffed they must not have stiffed	I must not have been stiffing you must not have been stiffing he must not have been stiffing we must not have been stiffing you must not have been stiffing they must not have been stiffing

Forma interrogativa

Forma simple	Forma con V-ing
must I stiff? must you stiff? must he stiff? must we stiff? must you stiff? must they stiff?	must I be stiffing? must you be stiffing? must he 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 he 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 he 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
must I not stiff? must you not stiff? must he not stiff? must we not stiff? must you not stiff? must they not stiff?	must I not be stiffing? must you not be stiffing? must he not be stiffing? must we not be stiffing? must you not be stiffing? must they not be stiffing?
Perfecto	Perfecto con V-ing
must I not have stiffed? must you not have stiffed? must he not have stiffed? must we not have stiffed? must you not have stiffed? must they not have stiffed?	must I not have been stiffing? must you not have been stiffing? must he not have been stiffing? must we not have been stiffing? must you not have been stiffing? must they not have been stiffing?