must preserve
Verbo regular: preserve - preserved- preserved

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must preserve
you must preserve
he must preserve
we must preserve
you must preserve
they must preserve 	I must be preserving
you must be preserving
he must be preserving
we must be preserving
you must be preserving
they must be preserving	I must have preserved
you must have preserved
he must have preserved
we must have preserved
you must have preserved
they must have preserved	I must have been preserving
you must have been preserving
he must have been preserving
we must have been preserving
you must have been preserving
they must have been preserving	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I mustn't preserve
you mustn't preserve
he mustn't preserve
we mustn't preserve
you mustn't preserve
they mustn't preserve 	I mustn't be preserving
you mustn't be preserving
he mustn't be preserving
we mustn't be preserving
you mustn't be preserving
they mustn't be preserving	I mustn't have preserved
you mustn't have preserved
he mustn't have preserved
we mustn't have preserved
you mustn't have preserved
they mustn't have preserved	I mustn't have been preserving
you mustn't have been preserving
he mustn't have been preserving
we mustn't have been preserving
you mustn't have been preserving
they mustn't have been preserving	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I preserve?
must you preserve?
must he preserve?
must we preserve?
must you preserve?
must they preserve? 	must I be preserving?
must you be preserving?
must he be preserving?
must we be preserving?
must you be preserving?
must they be preserving? 	must I have preserved?
must you have preserved?
must he have preserved?
must we have preserved?
must you have preserved?
must they have preserved? 	must I have been preserving?
must you have been preserving?
must he have been preserving?
must we have been preserving?
must you have been preserving?
must they have been preserving? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
mustn't I preserve?
mustn't you preserve?
mustn't he preserve?
mustn't we preserve?
mustn't you preserve?
mustn't they preserve? 	mustn't I be preserving?
mustn't you be preserving?
mustn't he be preserving?
mustn't we be preserving?
mustn't you be preserving?
mustn't they be preserving? 	mustn't I have preserved?
mustn't you have preserved?
mustn't he have preserved?
mustn't we have preserved?
mustn't you have preserved?
mustn't they have preserved? 	mustn't I have been preserving?
mustn't you have been preserving?
mustn't he have been preserving?
mustn't we have been preserving?
mustn't you have been preserving?
mustn't they have been preserving?