你不是和他合作过你的一本书吗？

Didn't you ___collaborate with him on one of your books?

在项目期间，他们合作过的员工既友好又乐于助人。

The staff they ___collaborated with were friendly and helpful during the project.

要解决复杂的全球性问题，各国必须合作并汇集专业知识。

To solve complex global issues, nations must ___collaborate and pool their expertise.