could interpolate
Regular verb: interpolate - interpolated- interpolated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could interpolate
you could interpolate
she could interpolate
we could interpolate
you could interpolate
they could interpolate 	I could be interpolating
you could be interpolating
she could be interpolating
we could be interpolating
you could be interpolating
they could be interpolating	I could have interpolated
you could have interpolated
she could have interpolated
we could have interpolated
you could have interpolated
they could have interpolated	I could have been interpolating
you could have been interpolating
she could have been interpolating
we could have been interpolating
you could have been interpolating
they could have been interpolating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't interpolate
you couldn't interpolate
she couldn't interpolate
we couldn't interpolate
you couldn't interpolate
they couldn't interpolate 	I couldn't be interpolating
you couldn't be interpolating
she couldn't be interpolating
we couldn't be interpolating
you couldn't be interpolating
they couldn't be interpolating	I couldn't have interpolated
you couldn't have interpolated
she couldn't have interpolated
we couldn't have interpolated
you couldn't have interpolated
they couldn't have interpolated	I couldn't have been interpolating
you couldn't have been interpolating
she couldn't have been interpolating
we couldn't have been interpolating
you couldn't have been interpolating
they couldn't have been interpolating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I interpolate?
could you interpolate?
could she interpolate?
could we interpolate?
could you interpolate?
could they interpolate? 	could I be interpolating?
could you be interpolating?
could she be interpolating?
could we be interpolating?
could you be interpolating?
could they be interpolating? 	could I have interpolated?
could you have interpolated?
could she have interpolated?
could we have interpolated?
could you have interpolated?
could they have interpolated? 	could I have been interpolating?
could you have been interpolating?
could she have been interpolating?
could we have been interpolating?
could you have been interpolating?
could they have been interpolating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I interpolate?
couldn't you interpolate?
couldn't she interpolate?
couldn't we interpolate?
couldn't you interpolate?
couldn't they interpolate? 	couldn't I be interpolating?
couldn't you be interpolating?
couldn't she be interpolating?
couldn't we be interpolating?
couldn't you be interpolating?
couldn't they be interpolating? 	couldn't I have interpolated?
couldn't you have interpolated?
couldn't she have interpolated?
couldn't we have interpolated?
couldn't you have interpolated?
couldn't they have interpolated? 	couldn't I have been interpolating?
couldn't you have been interpolating?
couldn't she have been interpolating?
couldn't we have been interpolating?
couldn't you have been interpolating?
couldn't they have been interpolating?