论述郑和下西洋面临的卫生环境及随船医生们的医疗实践对郑和下西洋的保障作用；

Elaborates sanitary condition which Zheng He's voyages to the West faces and along with the ship doctors' medical practice to safeguard of Zheng He's voyages to the West;

丹尼尔:我们学了郑和下西洋的故事。

Daniel: We've learnt the story of Zheng He “Sailing to West Ocean”.

它所面对的是六百年前一项伟大的事业--郑和下西洋。

It tells of a grand undertaking of seven journeys made by Chinese fleets 600 years ago.

郑和下西洋在随后的多年都对那些国家的文化和政治产生了重要影响，

These voyages left an important influence on the culture and politics of those nations for years on.