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
she must preserve
we must preserve
you must preserve
they must preserve 	I must be preserving
you must be preserving
she must be preserving
we must be preserving
you must be preserving
they must be preserving	I must have preserved
you must have preserved
she 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
she 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 must not preserve
you must not preserve
she must not preserve
we must not preserve
you must not preserve
they must not preserve 	I must not be preserving
you must not be preserving
she must not be preserving
we must not be preserving
you must not be preserving
they must not be preserving	I must not have preserved
you must not have preserved
she must not have preserved
we must not have preserved
you must not have preserved
they must not have preserved	I must not have been preserving
you must not have been preserving
she must not have been preserving
we must not have been preserving
you must not have been preserving
they must not have been preserving	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I preserve?
must you preserve?
must she preserve?
must we preserve?
must you preserve?
must they preserve? 	must I be preserving?
must you be preserving?
must she be preserving?
must we be preserving?
must you be preserving?
must they be preserving? 	must I have preserved?
must you have preserved?
must she 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 she 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 	
must I not preserve?
must you not preserve?
must she not preserve?
must we not preserve?
must you not preserve?
must they not preserve? 	must I not be preserving?
must you not be preserving?
must she not be preserving?
must we not be preserving?
must you not be preserving?
must they not be preserving? 	must I not have preserved?
must you not have preserved?
must she not have preserved?
must we not have preserved?
must you not have preserved?
must they not have preserved? 	must I not have been preserving?
must you not have been preserving?
must she not have been preserving?
must we not have been preserving?
must you not have been preserving?
must they not have been preserving?