can alter
Verbo regular: alter - altered- altered

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I can alter
you can alter
she can alter
we can alter
you can alter
they can alter 	I can be altering
you can be altering
she can be altering
we can be altering
you can be altering
they can be altering	I can have altered
you can have altered
she can have altered
we can have altered
you can have altered
they can have altered	I can have been altering
you can have been altering
she can have been altering
we can have been altering
you can have been altering
they can have been altering	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I can't alter
you can't alter
she can't alter
we can't alter
you can't alter
they can't alter 	I can't be altering
you can't be altering
she can't be altering
we can't be altering
you can't be altering
they can't be altering	I can't have altered
you can't have altered
she can't have altered
we can't have altered
you can't have altered
they can't have altered	I can't have been altering
you can't have been altering
she can't have been altering
we can't have been altering
you can't have been altering
they can't have been altering	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
can I alter?
can you alter?
can she alter?
can we alter?
can you alter?
can they alter? 	can I be altering?
can you be altering?
can she be altering?
can we be altering?
can you be altering?
can they be altering? 	can I have altered?
can you have altered?
can she have altered?
can we have altered?
can you have altered?
can they have altered? 	can I have been altering?
can you have been altering?
can she have been altering?
can we have been altering?
can you have been altering?
can they have been altering? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
can't I alter?
can't you alter?
can't she alter?
can't we alter?
can't you alter?
can't they alter? 	can't I be altering?
can't you be altering?
can't she be altering?
can't we be altering?
can't you be altering?
can't they be altering? 	can't I have altered?
can't you have altered?
can't she have altered?
can't we have altered?
can't you have altered?
can't they have altered? 	can't I have been altering?
can't you have been altering?
can't she have been altering?
can't we have been altering?
can't you have been altering?
can't they have been altering?