The project my colleagues and I had a party to celebrate it.A. completedB. was completed

问题补充：

The project, my colleagues and I had a party to celebrate it.

A. completed

B. was completed

C. had completed

D. completing

答案：

(答案→)A. completed

B. was completed

C. had completed

D. completing

解析：句意：项目完成了，我和同事举办了聚会庆祝。因为中间有逗号，但是没有连词，说明前面的不是句子，而是独立主格结构做状语，用逻辑主语+非谓语动词，因为the project和complete是被动关系，所以用过去分词，选A。