1 to work with sb else to achieve sth 合作;协力:
Our company is cooperating with a Danish firm on this project.我们公司与一家丹麦公司在这项目上合作。
2 to be helpful by doing what sb asks you to do 合作;协助:
If everyone cooperates by following the instructions, there will be no problem.如果人人都遵循指示办事就不会有问题。