I must founder you must founder he must founder we must founder you must founder they must founder
Forma con V-ing
I must be foundering you must be foundering he must be foundering we must be foundering you must be foundering they must be foundering
Perfecto
I must have foundered you must have foundered he must have foundered we must have foundered you must have foundered they must have foundered
Perfecto con V-ing
I must have been foundering you must have been foundering he must have been foundering we must have been foundering you must have been foundering they must have been foundering
Negación
Forma simple
I mustn't founder you mustn't founder he mustn't founder we mustn't founder you mustn't founder they mustn't founder
Forma con V-ing
I mustn't be foundering you mustn't be foundering he mustn't be foundering we mustn't be foundering you mustn't be foundering they mustn't be foundering
Perfecto
I mustn't have foundered you mustn't have foundered he mustn't have foundered we mustn't have foundered you mustn't have foundered they mustn't have foundered
Perfecto con V-ing
I mustn't have been foundering you mustn't have been foundering he mustn't have been foundering we mustn't have been foundering you mustn't have been foundering they mustn't have been foundering
Forma interrogativa
Forma simple
must I founder? must you founder? must he founder? must we founder? must you founder? must they founder?
Forma con V-ing
must I be foundering? must you be foundering? must he be foundering? must we be foundering? must you be foundering? must they be foundering?
Perfecto
must I have foundered? must you have foundered? must he have foundered? must we have foundered? must you have foundered? must they have foundered?
Perfecto con V-ing
must I have been foundering? must you have been foundering? must he have been foundering? must we have been foundering? must you have been foundering? must they have been foundering?
Forma interro-negativa
Forma simple
mustn't I founder? mustn't you founder? mustn't he founder? mustn't we founder? mustn't you founder? mustn't they founder?
Forma con V-ing
mustn't I be foundering? mustn't you be foundering? mustn't he be foundering? mustn't we be foundering? mustn't you be foundering? mustn't they be foundering?
Perfecto
mustn't I have foundered? mustn't you have foundered? mustn't he have foundered? mustn't we have foundered? mustn't you have foundered? mustn't they have foundered?
Perfecto con V-ing
mustn't I have been foundering? mustn't you have been foundering? mustn't he have been foundering? mustn't we have been foundering? mustn't you have been foundering? mustn't they have been foundering?