collaboration协作;合著(col+labor劳动+ation→***同劳动)
(1) Cooperate 即 work or act together for a common purpose or benefit ，意为“通力合作”，或“***同努力”，例如：
The army, navy, and air force cooperated in the assault.
陆海空三军协同实施突击。（陆谷孙《英汉大词典》）
名词cooperation 的例子：
With the cooperation of all the employees the work was done on time.
在全体雇员的***同努力下，工作按时完成。
(2) Collaborate 即 work jointly or together, especially on a literary project ，或 cooperate with an enemy nation ，意为“携手合作”（尤指文化艺术项目），或“与敌勾结”，例如：
She agreed to collaborate with him in writing her biography.
她同意与他合作撰写她的传记。（《牛津高阶英汉双解词典》第六版）
Those who collaborated with the enemy during the war were punished afterwards.
战时通敌者后来受到惩罚。
名词collaboration 的例子：
The two companies are working in close collaboration.
这两间公司正紧密协作。（《朗文当代高级辞典》第一版）