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 could not stamp you could not stamp he could not stamp we could not stamp you could not stamp they could not stamp	I could not be stamping you could not be stamping he could not be stamping we could not be stamping you could not be stamping they could not be stamping
Perfect	V-ing perfect
I could not have stamped you could not have stamped he could not have stamped we could not have stamped you could not have stamped they could not have stamped	I could not have been stamping you could not have been stamping he could not have been stamping we could not have been stamping you could not have been stamping they could not 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
could I not stamp? could you not stamp? could he not stamp? could we not stamp? could you not stamp? could they not stamp?	could I not be stamping? could you not be stamping? could he not be stamping? could we not be stamping? could you not be stamping? could they not be stamping?
Perfect	V-ing perfect
could I not have stamped? could you not have stamped? could he not have stamped? could we not have stamped? could you not have stamped? could they not have stamped?	could I not have been stamping? could you not have been stamping? could he not have been stamping? could we not have been stamping? could you not have been stamping? could they not have been stamping?