她正在写一篇关于美国诗歌的学位论文。

She's writing a ___dissertation on American poetry.

我已经完成了关于抗真菌研究的学位论文工作。

I have completed my ___dissertation work on antifungal studies.

他的学位论文专注于气候变化对海洋生态系统的影响。

His ___dissertation focuses on the impact of climate change on marine ecosystems.