could stamp
Regular verb: stamp - stamped- stamped

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
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	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 	Perfect 	V-ing perfect 	
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	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 	Perfect 	V-ing perfect 	
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? 	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 	Perfect 	V-ing perfect 	
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? 	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?