must rust
Verbo regular: rust - rusted- rusted

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must rust
you must rust
he must rust
we must rust
you must rust
they must rust 	I must be rusting
you must be rusting
he must be rusting
we must be rusting
you must be rusting
they must be rusting	I must have rusted
you must have rusted
he must have rusted
we must have rusted
you must have rusted
they must have rusted	I must have been rusting
you must have been rusting
he must have been rusting
we must have been rusting
you must have been rusting
they must have been rusting	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I must not rust
you must not rust
he must not rust
we must not rust
you must not rust
they must not rust 	I must not be rusting
you must not be rusting
he must not be rusting
we must not be rusting
you must not be rusting
they must not be rusting	I must not have rusted
you must not have rusted
he must not have rusted
we must not have rusted
you must not have rusted
they must not have rusted	I must not have been rusting
you must not have been rusting
he must not have been rusting
we must not have been rusting
you must not have been rusting
they must not have been rusting	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I rust?
must you rust?
must he rust?
must we rust?
must you rust?
must they rust? 	must I be rusting?
must you be rusting?
must he be rusting?
must we be rusting?
must you be rusting?
must they be rusting? 	must I have rusted?
must you have rusted?
must he have rusted?
must we have rusted?
must you have rusted?
must they have rusted? 	must I have been rusting?
must you have been rusting?
must he have been rusting?
must we have been rusting?
must you have been rusting?
must they have been rusting? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
must I not rust?
must you not rust?
must he not rust?
must we not rust?
must you not rust?
must they not rust? 	must I not be rusting?
must you not be rusting?
must he not be rusting?
must we not be rusting?
must you not be rusting?
must they not be rusting? 	must I not have rusted?
must you not have rusted?
must he not have rusted?
must we not have rusted?
must you not have rusted?
must they not have rusted? 	must I not have been rusting?
must you not have been rusting?
must he not have been rusting?
must we not have been rusting?
must you not have been rusting?
must they not have been rusting?