English verb conjugation
COULD EXPIRE

Regular verb: expire - expired - expired

Affirmation

Simple form	V-ing form
I could expire you could expire he could expire we could expire you could expire they could expire	I could be expiring you could be expiring he could be expiring we could be expiring you could be expiring they could be expiring
Perfect	V-ing perfect
I could have expired you could have expired he could have expired we could have expired you could have expired they could have expired	I could have been expiring you could have been expiring he could have been expiring we could have been expiring you could have been expiring they could have been expiring

Negation

Simple form	V-ing form
I couldn't expire you couldn't expire he couldn't expire we couldn't expire you couldn't expire they couldn't expire	I couldn't be expiring you couldn't be expiring he couldn't be expiring we couldn't be expiring you couldn't be expiring they couldn't be expiring
Perfect	V-ing perfect
I couldn't have expired you couldn't have expired he couldn't have expired we couldn't have expired you couldn't have expired they couldn't have expired	I couldn't have been expiring you couldn't have been expiring he couldn't have been expiring we couldn't have been expiring you couldn't have been expiring they couldn't have been expiring

Interrogative form

Simple form	V-ing form
could I expire? could you expire? could he expire? could we expire? could you expire? could they expire?	could I be expiring? could you be expiring? could he be expiring? could we be expiring? could you be expiring? could they be expiring?
Perfect	V-ing perfect
could I have expired? could you have expired? could he have expired? could we have expired? could you have expired? could they have expired?	could I have been expiring? could you have been expiring? could he have been expiring? could we have been expiring? could you have been expiring? could they have been expiring?

Interro-negative form

Simple form	V-ing form
couldn't I expire? couldn't you expire? couldn't he expire? couldn't we expire? couldn't you expire? couldn't they expire?	couldn't I be expiring? couldn't you be expiring? couldn't he be expiring? couldn't we be expiring? couldn't you be expiring? couldn't they be expiring?
Perfect	V-ing perfect
couldn't I have expired? couldn't you have expired? couldn't he have expired? couldn't we have expired? couldn't you have expired? couldn't they have expired?	couldn't I have been expiring? couldn't you have been expiring? couldn't he have been expiring? couldn't we have been expiring? couldn't you have been expiring? couldn't they have been expiring?