umpty

例句：

1. 1. The scientist discovered an unknown substance in the sample.
   科学家在样本中发现了未知物质。
2. 2. The team is working on an unknown project.
   团队正在研究一个未知项目。
3. 3.The researchers are trying to understand the unknown origins of the virus.
   研究人员正试图了解这种病毒未知的起源。