could negotiate
Regular verb: negotiate - negotiated- negotiated

Affirmation 	
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I could negotiate
you could negotiate
he could negotiate
we could negotiate
you could negotiate
they could negotiate 	I could be negotiating
you could be negotiating
he could be negotiating
we could be negotiating
you could be negotiating
they could be negotiating	I could have negotiated
you could have negotiated
he could have negotiated
we could have negotiated
you could have negotiated
they could have negotiated	I could have been negotiating
you could have been negotiating
he could have been negotiating
we could have been negotiating
you could have been negotiating
they could have been negotiating	

Negation 	
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I couldn't negotiate
you couldn't negotiate
he couldn't negotiate
we couldn't negotiate
you couldn't negotiate
they couldn't negotiate 	I couldn't be negotiating
you couldn't be negotiating
he couldn't be negotiating
we couldn't be negotiating
you couldn't be negotiating
they couldn't be negotiating	I couldn't have negotiated
you couldn't have negotiated
he couldn't have negotiated
we couldn't have negotiated
you couldn't have negotiated
they couldn't have negotiated	I couldn't have been negotiating
you couldn't have been negotiating
he couldn't have been negotiating
we couldn't have been negotiating
you couldn't have been negotiating
they couldn't have been negotiating	

Interrogative form 	
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could I negotiate?
could you negotiate?
could he negotiate?
could we negotiate?
could you negotiate?
could they negotiate? 	could I be negotiating?
could you be negotiating?
could he be negotiating?
could we be negotiating?
could you be negotiating?
could they be negotiating? 	could I have negotiated?
could you have negotiated?
could he have negotiated?
could we have negotiated?
could you have negotiated?
could they have negotiated? 	could I have been negotiating?
could you have been negotiating?
could he have been negotiating?
could we have been negotiating?
could you have been negotiating?
could they have been negotiating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I negotiate?
couldn't you negotiate?
couldn't he negotiate?
couldn't we negotiate?
couldn't you negotiate?
couldn't they negotiate? 	couldn't I be negotiating?
couldn't you be negotiating?
couldn't he be negotiating?
couldn't we be negotiating?
couldn't you be negotiating?
couldn't they be negotiating? 	couldn't I have negotiated?
couldn't you have negotiated?
couldn't he have negotiated?
couldn't we have negotiated?
couldn't you have negotiated?
couldn't they have negotiated? 	couldn't I have been negotiating?
couldn't you have been negotiating?
couldn't he have been negotiating?
couldn't we have been negotiating?
couldn't you have been negotiating?
couldn't they have been negotiating?