No one knows what triggered the vomiting syndrome, but stress is often a causative factor - so even that might have been linked to the disorders Darwin gained during the voyage.

没有人知道是什么导致了呕吐综合症，但压力通常是一个诱因-甚至也可能与达尔文在航海旅行中患上的失调症有关联。

youdao

Everyone knows this and it’s the reason so many people put off following their passion; they don’t want to find out that no one cares, and no one wants to buy what they have to offer.

每个人都知道这个道理，并且这也是阻碍很多人追求他们爱好的原因；他们不希望发现没有人关注他们的努力，没有人想购买他们的产品。

youdao

No one knows why this should be so, though the study did find that the sunnier children were also more likely to drink and smoke in later life.

没有人知道为什么会这样，不过研究发现，越开朗的儿童在日后的生活中饮酒和吸烟的可能性也更大。

youdao

Experts say one of the reasons the gunfight is so interesting to many people is that no one knows who shot first or why.

VOA: special.2010.02.15

That means the song is so old, no one really knows who wrote it.

VOA: special.2009.07.27

"It's so complicated that no one really knows what to do, " says Prof Jankovic.

BBC: How Croatia and Serbia buried the hatchet

The country is so vast and roadless that no one knows, to the nearest million, how many people died in the war, let alone how many potential voters live there now.

ECONOMIST: Democratic Republic of Congo

She had access to a phone and a computer, so obviously something went on that no one knows about.

CNN: Kidnap victim's daughters' lives seemed normal, friend says