English verb conjugation
COULD FLAG

Regular verb: flag - flagged - flagged

Affirmation

Simple form	V-ing form
I could flag you could flag he could flag we could flag you could flag they could flag	I could be flagging you could be flagging he could be flagging we could be flagging you could be flagging they could be flagging
Perfect	V-ing perfect
I could have flagged you could have flagged he could have flagged we could have flagged you could have flagged they could have flagged	I could have been flagging you could have been flagging he could have been flagging we could have been flagging you could have been flagging they could have been flagging

Negation

Simple form	V-ing form
I couldn't flag you couldn't flag he couldn't flag we couldn't flag you couldn't flag they couldn't flag	I couldn't be flagging you couldn't be flagging he couldn't be flagging we couldn't be flagging you couldn't be flagging they couldn't be flagging
Perfect	V-ing perfect
I couldn't have flagged you couldn't have flagged he couldn't have flagged we couldn't have flagged you couldn't have flagged they couldn't have flagged	I couldn't have been flagging you couldn't have been flagging he couldn't have been flagging we couldn't have been flagging you couldn't have been flagging they couldn't have been flagging

Interrogative form

Simple form	V-ing form
could I flag? could you flag? could he flag? could we flag? could you flag? could they flag?	could I be flagging? could you be flagging? could he be flagging? could we be flagging? could you be flagging? could they be flagging?
Perfect	V-ing perfect
could I have flagged? could you have flagged? could he have flagged? could we have flagged? could you have flagged? could they have flagged?	could I have been flagging? could you have been flagging? could he have been flagging? could we have been flagging? could you have been flagging? could they have been flagging?

Interro-negative form

Simple form	V-ing form
couldn't I flag? couldn't you flag? couldn't he flag? couldn't we flag? couldn't you flag? couldn't they flag?	couldn't I be flagging? couldn't you be flagging? couldn't he be flagging? couldn't we be flagging? couldn't you be flagging? couldn't they be flagging?
Perfect	V-ing perfect
couldn't I have flagged? couldn't you have flagged? couldn't he have flagged? couldn't we have flagged? couldn't you have flagged? couldn't they have flagged?	couldn't I have been flagging? couldn't you have been flagging? couldn't he have been flagging? couldn't we have been flagging? couldn't you have been flagging? couldn't they have been flagging?