could refract
Regular verb: refract - refracted- refracted

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could refract
you could refract
she could refract
we could refract
you could refract
they could refract 	I could be refracting
you could be refracting
she could be refracting
we could be refracting
you could be refracting
they could be refracting	I could have refracted
you could have refracted
she could have refracted
we could have refracted
you could have refracted
they could have refracted	I could have been refracting
you could have been refracting
she could have been refracting
we could have been refracting
you could have been refracting
they could have been refracting	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't refract
you couldn't refract
she couldn't refract
we couldn't refract
you couldn't refract
they couldn't refract 	I couldn't be refracting
you couldn't be refracting
she couldn't be refracting
we couldn't be refracting
you couldn't be refracting
they couldn't be refracting	I couldn't have refracted
you couldn't have refracted
she couldn't have refracted
we couldn't have refracted
you couldn't have refracted
they couldn't have refracted	I couldn't have been refracting
you couldn't have been refracting
she couldn't have been refracting
we couldn't have been refracting
you couldn't have been refracting
they couldn't have been refracting	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I refract?
could you refract?
could she refract?
could we refract?
could you refract?
could they refract? 	could I be refracting?
could you be refracting?
could she be refracting?
could we be refracting?
could you be refracting?
could they be refracting? 	could I have refracted?
could you have refracted?
could she have refracted?
could we have refracted?
could you have refracted?
could they have refracted? 	could I have been refracting?
could you have been refracting?
could she have been refracting?
could we have been refracting?
could you have been refracting?
could they have been refracting? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I refract?
couldn't you refract?
couldn't she refract?
couldn't we refract?
couldn't you refract?
couldn't they refract? 	couldn't I be refracting?
couldn't you be refracting?
couldn't she be refracting?
couldn't we be refracting?
couldn't you be refracting?
couldn't they be refracting? 	couldn't I have refracted?
couldn't you have refracted?
couldn't she have refracted?
couldn't we have refracted?
couldn't you have refracted?
couldn't they have refracted? 	couldn't I have been refracting?
couldn't you have been refracting?
couldn't she have been refracting?
couldn't we have been refracting?
couldn't you have been refracting?
couldn't they have been refracting?