English verb conjugation
COULD PIN

Regular verb: pin - pinned - pinned

Affirmation

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