Simple past tense and past participle of cooperate.(verb)
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Use "co-operated" in a sentence
"They have co-operated on (I think) all of Jans movies, some of them you might have heard of - Dark Blue World, Kolja and more."
"Whether the McCanns are guilty or innocent, they have never co-operated with the Portuguese police which you would expect genuine parents to do."
"They write: Subjects exposed to higher levels of testosterone during foetal development did not co-operate less than the rest and even co-operated more than subjects with average levels."