(1) Cooperate 即 work or act together for a common purpose or benefit ，意為“通力合作”，或“***同努力”，例如：
The army, navy, and air force cooperated in the assault.
陸海空三軍協同實施突擊。（陸谷孫《英漢大詞典》）
名詞cooperation 的例子：
With the cooperation of all the employees the work was done on time.
在全體雇員的***同努力下，工作按時完成。
(2) Collaborate 即 work jointly or together, especially on a literary project ，或 cooperate with an enemy nation ，意為“攜手合作”（尤指文化藝術項目），或“與敵勾結”，例如：
She agreed to collaborate with him in writing her biography.
她同意與他合作撰寫她的傳記。（《牛津高階英漢雙解詞典》第六版）
Those who collaborated with the enemy during the war were punished afterwards.
戰時通敵者後來受到懲罰。
名詞collaboration 的例子：
The two companies are working in close collaboration.
這兩間公司正緊密協作。（《朗文當代高級辭典》第壹版）