English verb conjugation
COULD STAMP

Regular verb: stamp - stamped - stamped

Affirmation

Simple form	V-ing form
I could stamp you could stamp he could stamp we could stamp you could stamp they could stamp	I could be stamping you could be stamping he could be stamping we could be stamping you could be stamping they could be stamping
Perfect	V-ing perfect
I could have stamped you could have stamped he could have stamped we could have stamped you could have stamped they could have stamped	I could have been stamping you could have been stamping he could have been stamping we could have been stamping you could have been stamping they could have been stamping

Negation

Simple form	V-ing form
I couldn't stamp you couldn't stamp he couldn't stamp we couldn't stamp you couldn't stamp they couldn't stamp	I couldn't be stamping you couldn't be stamping he couldn't be stamping we couldn't be stamping you couldn't be stamping they couldn't be stamping
Perfect	V-ing perfect
I couldn't have stamped you couldn't have stamped he couldn't have stamped we couldn't have stamped you couldn't have stamped they couldn't have stamped	I couldn't have been stamping you couldn't have been stamping he couldn't have been stamping we couldn't have been stamping you couldn't have been stamping they couldn't have been stamping

Interrogative form

Simple form	V-ing form
could I stamp? could you stamp? could he stamp? could we stamp? could you stamp? could they stamp?	could I be stamping? could you be stamping? could he be stamping? could we be stamping? could you be stamping? could they be stamping?
Perfect	V-ing perfect
could I have stamped? could you have stamped? could he have stamped? could we have stamped? could you have stamped? could they have stamped?	could I have been stamping? could you have been stamping? could he have been stamping? could we have been stamping? could you have been stamping? could they have been stamping?

Interro-negative form

Simple form	V-ing form
couldn't I stamp? couldn't you stamp? couldn't he stamp? couldn't we stamp? couldn't you stamp? couldn't they stamp?	couldn't I be stamping? couldn't you be stamping? couldn't he be stamping? couldn't we be stamping? couldn't you be stamping? couldn't they be stamping?
Perfect	V-ing perfect
couldn't I have stamped? couldn't you have stamped? couldn't he have stamped? couldn't we have stamped? couldn't you have stamped? couldn't they have stamped?	couldn't I have been stamping? couldn't you have been stamping? couldn't he have been stamping? couldn't we have been stamping? couldn't you have been stamping? couldn't they have been stamping?