Translation of "Diploma" in Chinese

My father died before I got my diploma.

我父亲在我毕业之前就过世了。

The principal presented each of the graduates with diploma.

校长向每个毕业生颁发了毕业证书。

If there's something more terrifying in the world than eternity, then it's probably the current progress of my diploma thesis.

如果有什么比以往任何时候在世界上可怕的，它是我的论文目前的发展。