English verb conjugation
COULD POSTMARK

Regular verb: postmark - postmarked - postmarked

Affirmation

Simple form	V-ing form
I could postmark you could postmark she could postmark we could postmark you could postmark they could postmark	I could be postmarking you could be postmarking she could be postmarking we could be postmarking you could be postmarking they could be postmarking
Perfect	V-ing perfect
I could have postmarked you could have postmarked she could have postmarked we could have postmarked you could have postmarked they could have postmarked	I could have been postmarking you could have been postmarking she could have been postmarking we could have been postmarking you could have been postmarking they could have been postmarking

Negation

Simple form	V-ing form
I couldn't postmark you couldn't postmark she couldn't postmark we couldn't postmark you couldn't postmark they couldn't postmark	I couldn't be postmarking you couldn't be postmarking she couldn't be postmarking we couldn't be postmarking you couldn't be postmarking they couldn't be postmarking
Perfect	V-ing perfect
I couldn't have postmarked you couldn't have postmarked she couldn't have postmarked we couldn't have postmarked you couldn't have postmarked they couldn't have postmarked	I couldn't have been postmarking you couldn't have been postmarking she couldn't have been postmarking we couldn't have been postmarking you couldn't have been postmarking they couldn't have been postmarking

Interrogative form

Simple form	V-ing form
could I postmark? could you postmark? could she postmark? could we postmark? could you postmark? could they postmark?	could I be postmarking? could you be postmarking? could she be postmarking? could we be postmarking? could you be postmarking? could they be postmarking?
Perfect	V-ing perfect
could I have postmarked? could you have postmarked? could she have postmarked? could we have postmarked? could you have postmarked? could they have postmarked?	could I have been postmarking? could you have been postmarking? could she have been postmarking? could we have been postmarking? could you have been postmarking? could they have been postmarking?

Interro-negative form

Simple form	V-ing form
couldn't I postmark? couldn't you postmark? couldn't she postmark? couldn't we postmark? couldn't you postmark? couldn't they postmark?	couldn't I be postmarking? couldn't you be postmarking? couldn't she be postmarking? couldn't we be postmarking? couldn't you be postmarking? couldn't they be postmarking?
Perfect	V-ing perfect
couldn't I have postmarked? couldn't you have postmarked? couldn't she have postmarked? couldn't we have postmarked? couldn't you have postmarked? couldn't they have postmarked?	couldn't I have been postmarking? couldn't you have been postmarking? couldn't she have been postmarking? couldn't we have been postmarking? couldn't you have been postmarking? couldn't they have been postmarking?