could authenticate
Verbo regular: authenticate - authenticated- authenticated

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could authenticate
you could authenticate
he could authenticate
we could authenticate
you could authenticate
they could authenticate 	I could be authenticating
you could be authenticating
he could be authenticating
we could be authenticating
you could be authenticating
they could be authenticating	I could have authenticated
you could have authenticated
he could have authenticated
we could have authenticated
you could have authenticated
they could have authenticated	I could have been authenticating
you could have been authenticating
he could have been authenticating
we could have been authenticating
you could have been authenticating
they could have been authenticating	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't authenticate
you couldn't authenticate
he couldn't authenticate
we couldn't authenticate
you couldn't authenticate
they couldn't authenticate 	I couldn't be authenticating
you couldn't be authenticating
he couldn't be authenticating
we couldn't be authenticating
you couldn't be authenticating
they couldn't be authenticating	I couldn't have authenticated
you couldn't have authenticated
he couldn't have authenticated
we couldn't have authenticated
you couldn't have authenticated
they couldn't have authenticated	I couldn't have been authenticating
you couldn't have been authenticating
he couldn't have been authenticating
we couldn't have been authenticating
you couldn't have been authenticating
they couldn't have been authenticating	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I authenticate?
could you authenticate?
could he authenticate?
could we authenticate?
could you authenticate?
could they authenticate? 	could I be authenticating?
could you be authenticating?
could he be authenticating?
could we be authenticating?
could you be authenticating?
could they be authenticating? 	could I have authenticated?
could you have authenticated?
could he have authenticated?
could we have authenticated?
could you have authenticated?
could they have authenticated? 	could I have been authenticating?
could you have been authenticating?
could he have been authenticating?
could we have been authenticating?
could you have been authenticating?
could they have been authenticating? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I authenticate?
couldn't you authenticate?
couldn't he authenticate?
couldn't we authenticate?
couldn't you authenticate?
couldn't they authenticate? 	couldn't I be authenticating?
couldn't you be authenticating?
couldn't he be authenticating?
couldn't we be authenticating?
couldn't you be authenticating?
couldn't they be authenticating? 	couldn't I have authenticated?
couldn't you have authenticated?
couldn't he have authenticated?
couldn't we have authenticated?
couldn't you have authenticated?
couldn't they have authenticated? 	couldn't I have been authenticating?
couldn't you have been authenticating?
couldn't he have been authenticating?
couldn't we have been authenticating?
couldn't you have been authenticating?
couldn't they have been authenticating?