English verb conjugation
COULD AUTHENTICATE

Regular verb: authenticate - authenticated - authenticated

Affirmation

Simple form	V-ing form
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
Perfect	V-ing perfect
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

Negation

Simple form	V-ing form
I could not authenticate you could not authenticate he could not authenticate we could not authenticate you could not authenticate they could not authenticate	I could not be authenticating you could not be authenticating he could not be authenticating we could not be authenticating you could not be authenticating they could not be authenticating
Perfect	V-ing perfect
I could not have authenticated you could not have authenticated he could not have authenticated we could not have authenticated you could not have authenticated they could not have authenticated	I could not have been authenticating you could not have been authenticating he could not have been authenticating we could not have been authenticating you could not have been authenticating they could not have been authenticating

Interrogative form

Simple form	V-ing form
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?
Perfect	V-ing perfect
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?

Interro-negative form

Simple form	V-ing form
could I not authenticate? could you not authenticate? could he not authenticate? could we not authenticate? could you not authenticate? could they not authenticate?	could I not be authenticating? could you not be authenticating? could he not be authenticating? could we not be authenticating? could you not be authenticating? could they not be authenticating?
Perfect	V-ing perfect
could I not have authenticated? could you not have authenticated? could he not have authenticated? could we not have authenticated? could you not have authenticated? could they not have authenticated?	could I not have been authenticating? could you not have been authenticating? could he not have been authenticating? could we not have been authenticating? could you not have been authenticating? could they not have been authenticating?