could duplicate
Regular verb: duplicate - duplicated- duplicated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could duplicate
you could duplicate
she could duplicate
we could duplicate
you could duplicate
they could duplicate 	I could be duplicating
you could be duplicating
she could be duplicating
we could be duplicating
you could be duplicating
they could be duplicating	I could have duplicated
you could have duplicated
she could have duplicated
we could have duplicated
you could have duplicated
they could have duplicated	I could have been duplicating
you could have been duplicating
she could have been duplicating
we could have been duplicating
you could have been duplicating
they could have been duplicating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't duplicate
you couldn't duplicate
she couldn't duplicate
we couldn't duplicate
you couldn't duplicate
they couldn't duplicate 	I couldn't be duplicating
you couldn't be duplicating
she couldn't be duplicating
we couldn't be duplicating
you couldn't be duplicating
they couldn't be duplicating	I couldn't have duplicated
you couldn't have duplicated
she couldn't have duplicated
we couldn't have duplicated
you couldn't have duplicated
they couldn't have duplicated	I couldn't have been duplicating
you couldn't have been duplicating
she couldn't have been duplicating
we couldn't have been duplicating
you couldn't have been duplicating
they couldn't have been duplicating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I duplicate?
could you duplicate?
could she duplicate?
could we duplicate?
could you duplicate?
could they duplicate? 	could I be duplicating?
could you be duplicating?
could she be duplicating?
could we be duplicating?
could you be duplicating?
could they be duplicating? 	could I have duplicated?
could you have duplicated?
could she have duplicated?
could we have duplicated?
could you have duplicated?
could they have duplicated? 	could I have been duplicating?
could you have been duplicating?
could she have been duplicating?
could we have been duplicating?
could you have been duplicating?
could they have been duplicating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I duplicate?
couldn't you duplicate?
couldn't she duplicate?
couldn't we duplicate?
couldn't you duplicate?
couldn't they duplicate? 	couldn't I be duplicating?
couldn't you be duplicating?
couldn't she be duplicating?
couldn't we be duplicating?
couldn't you be duplicating?
couldn't they be duplicating? 	couldn't I have duplicated?
couldn't you have duplicated?
couldn't she have duplicated?
couldn't we have duplicated?
couldn't you have duplicated?
couldn't they have duplicated? 	couldn't I have been duplicating?
couldn't you have been duplicating?
couldn't she have been duplicating?
couldn't we have been duplicating?
couldn't you have been duplicating?
couldn't they have been duplicating?