could taper
Regular verb: taper - tapered- tapered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could taper
you could taper
he could taper
we could taper
you could taper
they could taper 	I could be tapering
you could be tapering
he could be tapering
we could be tapering
you could be tapering
they could be tapering	I could have tapered
you could have tapered
he could have tapered
we could have tapered
you could have tapered
they could have tapered	I could have been tapering
you could have been tapering
he could have been tapering
we could have been tapering
you could have been tapering
they could have been tapering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't taper
you couldn't taper
he couldn't taper
we couldn't taper
you couldn't taper
they couldn't taper 	I couldn't be tapering
you couldn't be tapering
he couldn't be tapering
we couldn't be tapering
you couldn't be tapering
they couldn't be tapering	I couldn't have tapered
you couldn't have tapered
he couldn't have tapered
we couldn't have tapered
you couldn't have tapered
they couldn't have tapered	I couldn't have been tapering
you couldn't have been tapering
he couldn't have been tapering
we couldn't have been tapering
you couldn't have been tapering
they couldn't have been tapering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I taper?
could you taper?
could he taper?
could we taper?
could you taper?
could they taper? 	could I be tapering?
could you be tapering?
could he be tapering?
could we be tapering?
could you be tapering?
could they be tapering? 	could I have tapered?
could you have tapered?
could he have tapered?
could we have tapered?
could you have tapered?
could they have tapered? 	could I have been tapering?
could you have been tapering?
could he have been tapering?
could we have been tapering?
could you have been tapering?
could they have been tapering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I taper?
couldn't you taper?
couldn't he taper?
couldn't we taper?
couldn't you taper?
couldn't they taper? 	couldn't I be tapering?
couldn't you be tapering?
couldn't he be tapering?
couldn't we be tapering?
couldn't you be tapering?
couldn't they be tapering? 	couldn't I have tapered?
couldn't you have tapered?
couldn't he have tapered?
couldn't we have tapered?
couldn't you have tapered?
couldn't they have tapered? 	couldn't I have been tapering?
couldn't you have been tapering?
couldn't he have been tapering?
couldn't we have been tapering?
couldn't you have been tapering?
couldn't they have been tapering?