Here the researchers must speculate a little. They suggest the answer may be the lack of association with other humans during the period of sleep.

这里研究者得做一些推测，他们认为答案可能是睡眠期间缺少与他人的交流。

youdao

Make no mistake, my brothers, the humans will draw first blood. When the air is still, and the night has fallen, there is only one question you must answer. Who will you stand with?

别犯错，弟兄们，人类将会先下毒手。万籁此俱寂，夜幕已降临，只有一个问题大家必须回答，你们到底站在哪一边？

youdao

Make no mistake, my brothers, the humans will draw first blood. When the air is still, and the night has fallen, there is only one question you must answer. Who will you stand with?

别犯错，弟兄们，人类将会先下毒手。万籁此俱寂，夜幕已降临，只有一个问题大家必须回答，你们到底站在哪一边？

youdao