English verb conjugation
COULD FROG

Regular verb: frog - froged - froged

Affirmation

Simple form	V-ing form
I could frog you could frog he could frog we could frog you could frog they could frog	I could be froging you could be froging he could be froging we could be froging you could be froging they could be froging
Perfect	V-ing perfect
I could have froged you could have froged he could have froged we could have froged you could have froged they could have froged	I could have been froging you could have been froging he could have been froging we could have been froging you could have been froging they could have been froging

Negation

Simple form	V-ing form
I couldn't frog you couldn't frog he couldn't frog we couldn't frog you couldn't frog they couldn't frog	I couldn't be froging you couldn't be froging he couldn't be froging we couldn't be froging you couldn't be froging they couldn't be froging
Perfect	V-ing perfect
I couldn't have froged you couldn't have froged he couldn't have froged we couldn't have froged you couldn't have froged they couldn't have froged	I couldn't have been froging you couldn't have been froging he couldn't have been froging we couldn't have been froging you couldn't have been froging they couldn't have been froging

Interrogative form

Simple form	V-ing form
could I frog? could you frog? could he frog? could we frog? could you frog? could they frog?	could I be froging? could you be froging? could he be froging? could we be froging? could you be froging? could they be froging?
Perfect	V-ing perfect
could I have froged? could you have froged? could he have froged? could we have froged? could you have froged? could they have froged?	could I have been froging? could you have been froging? could he have been froging? could we have been froging? could you have been froging? could they have been froging?

Interro-negative form

Simple form	V-ing form
couldn't I frog? couldn't you frog? couldn't he frog? couldn't we frog? couldn't you frog? couldn't they frog?	couldn't I be froging? couldn't you be froging? couldn't he be froging? couldn't we be froging? couldn't you be froging? couldn't they be froging?
Perfect	V-ing perfect
couldn't I have froged? couldn't you have froged? couldn't he have froged? couldn't we have froged? couldn't you have froged? couldn't they have froged?	couldn't I have been froging? couldn't you have been froging? couldn't he have been froging? couldn't we have been froging? couldn't you have been froging? couldn't they have been froging?