English verb conjugation
COULD PIN

Regular verb: pin - pinned - pinned

Affirmation

Simple form	V-ing form
I could pin you could pin he could pin we could pin you could pin they could pin	I could be pinning you could be pinning he could be pinning we could be pinning you could be pinning they could be pinning
Perfect	V-ing perfect
I could have pinned you could have pinned he could have pinned we could have pinned you could have pinned they could have pinned	I could have been pinning you could have been pinning he could have been pinning we could have been pinning you could have been pinning they could have been pinning

Negation

Simple form	V-ing form
I couldn't pin you couldn't pin he couldn't pin we couldn't pin you couldn't pin they couldn't pin	I couldn't be pinning you couldn't be pinning he couldn't be pinning we couldn't be pinning you couldn't be pinning they couldn't be pinning
Perfect	V-ing perfect
I couldn't have pinned you couldn't have pinned he couldn't have pinned we couldn't have pinned you couldn't have pinned they couldn't have pinned	I couldn't have been pinning you couldn't have been pinning he couldn't have been pinning we couldn't have been pinning you couldn't have been pinning they couldn't have been pinning

Interrogative form

Simple form	V-ing form
could I pin? could you pin? could he pin? could we pin? could you pin? could they pin?	could I be pinning? could you be pinning? could he be pinning? could we be pinning? could you be pinning? could they be pinning?
Perfect	V-ing perfect
could I have pinned? could you have pinned? could he have pinned? could we have pinned? could you have pinned? could they have pinned?	could I have been pinning? could you have been pinning? could he have been pinning? could we have been pinning? could you have been pinning? could they have been pinning?

Interro-negative form

Simple form	V-ing form
couldn't I pin? couldn't you pin? couldn't he pin? couldn't we pin? couldn't you pin? couldn't they pin?	couldn't I be pinning? couldn't you be pinning? couldn't he be pinning? couldn't we be pinning? couldn't you be pinning? couldn't they be pinning?
Perfect	V-ing perfect
couldn't I have pinned? couldn't you have pinned? couldn't he have pinned? couldn't we have pinned? couldn't you have pinned? couldn't they have pinned?	couldn't I have been pinning? couldn't you have been pinning? couldn't he have been pinning? couldn't we have been pinning? couldn't you have been pinning? couldn't they have been pinning?