English verb conjugation
COULD FROG

Regular verb: frog - froged - froged

Affirmation

Simple form	V-ing form
I could frog you could frog she could frog we could frog you could frog they could frog	I could be froging you could be froging she 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 she 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 she 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 she 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 she 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 she 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 she 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 she frog? could we frog? could you frog? could they frog?	could I be froging? could you be froging? could she 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 she 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 she 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 she 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 she 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 she 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 she have been froging? couldn't we have been froging? couldn't you have been froging? couldn't they have been froging?