may stack
Verbo regular: stack - stacked- stacked

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I may stack
you may stack
he may stack
we may stack
you may stack
they may stack 	I may be stacking
you may be stacking
he may be stacking
we may be stacking
you may be stacking
they may be stacking	I may have stacked
you may have stacked
he may have stacked
we may have stacked
you may have stacked
they may have stacked	I may have been stacking
you may have been stacking
he may have been stacking
we may have been stacking
you may have been stacking
they may have been stacking	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I may not stack
you may not stack
he may not stack
we may not stack
you may not stack
they may not stack 	I may not be stacking
you may not be stacking
he may not be stacking
we may not be stacking
you may not be stacking
they may not be stacking	I may not have stacked
you may not have stacked
he may not have stacked
we may not have stacked
you may not have stacked
they may not have stacked	I may not have been stacking
you may not have been stacking
he may not have been stacking
we may not have been stacking
you may not have been stacking
they may not have been stacking	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
may I stack?
may you stack?
may he stack?
may we stack?
may you stack?
may they stack? 	may I be stacking?
may you be stacking?
may he be stacking?
may we be stacking?
may you be stacking?
may they be stacking? 	may I have stacked?
may you have stacked?
may he have stacked?
may we have stacked?
may you have stacked?
may they have stacked? 	may I have been stacking?
may you have been stacking?
may he have been stacking?
may we have been stacking?
may you have been stacking?
may they have been stacking? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
may I not stack?
may you not stack?
may he not stack?
may we not stack?
may you not stack?
may they not stack? 	may I not be stacking?
may you not be stacking?
may he not be stacking?
may we not be stacking?
may you not be stacking?
may they not be stacking? 	may I not have stacked?
may you not have stacked?
may he not have stacked?
may we not have stacked?
may you not have stacked?
may they not have stacked? 	may I not have been stacking?
may you not have been stacking?
may he not have been stacking?
may we not have been stacking?
may you not have been stacking?
may they not have been stacking?