为什么白鲟不能人工繁殖？

Why couldn't the Chinese paddlefish be raised in captivity?

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为什么他不能人性化点？

Why can't [he] show me some humanity?

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Why are we unable to talk to a crowd as we talk to a single friend?

为什么我们不能跟一群人讲话,却可以单独同朋友高谈阔论？

耶鲁公开课 - 心理学导论课程节选

The general story of why we can't in general is because there's no surprise, there's no mock aggression, and also there may be a general deadening of self-stimulation.

为什么大部分人不能胳肢自己,是因为它在我们意料之内，没有打闹的侵略性，通常这种引自己笑的念头都会嘎然而止。

耶鲁公开课 - 心理学导论课程节选