这些玫瑰得了溃疡病，导致它们的茎干上出现了坏死的斑块。

The roses developed ___cankers, causing dead patches to appear on their stems.

网络暴力是侵蚀年轻人心理健康的毒瘤。

Cyberbullying is a ___canker that slowly poisons young people's mental health.

他嘴里的溃疡让他很难享受热汤。

The ___canker in his mouth made it difficult to enjoy hot soup.