must sustain
Verbo regular: sustain - sustained- sustained

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must sustain
you must sustain
she must sustain
we must sustain
you must sustain
they must sustain 	I must be sustaining
you must be sustaining
she must be sustaining
we must be sustaining
you must be sustaining
they must be sustaining	I must have sustained
you must have sustained
she must have sustained
we must have sustained
you must have sustained
they must have sustained	I must have been sustaining
you must have been sustaining
she must have been sustaining
we must have been sustaining
you must have been sustaining
they must have been sustaining	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must not sustain
you must not sustain
she must not sustain
we must not sustain
you must not sustain
they must not sustain 	I must not be sustaining
you must not be sustaining
she must not be sustaining
we must not be sustaining
you must not be sustaining
they must not be sustaining	I must not have sustained
you must not have sustained
she must not have sustained
we must not have sustained
you must not have sustained
they must not have sustained	I must not have been sustaining
you must not have been sustaining
she must not have been sustaining
we must not have been sustaining
you must not have been sustaining
they must not have been sustaining	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I sustain?
must you sustain?
must she sustain?
must we sustain?
must you sustain?
must they sustain? 	must I be sustaining?
must you be sustaining?
must she be sustaining?
must we be sustaining?
must you be sustaining?
must they be sustaining? 	must I have sustained?
must you have sustained?
must she have sustained?
must we have sustained?
must you have sustained?
must they have sustained? 	must I have been sustaining?
must you have been sustaining?
must she have been sustaining?
must we have been sustaining?
must you have been sustaining?
must they have been sustaining? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I not sustain?
must you not sustain?
must she not sustain?
must we not sustain?
must you not sustain?
must they not sustain? 	must I not be sustaining?
must you not be sustaining?
must she not be sustaining?
must we not be sustaining?
must you not be sustaining?
must they not be sustaining? 	must I not have sustained?
must you not have sustained?
must she not have sustained?
must we not have sustained?
must you not have sustained?
must they not have sustained? 	must I not have been sustaining?
must you not have been sustaining?
must she not have been sustaining?
must we not have been sustaining?
must you not have been sustaining?
must they not have been sustaining?