It's definitely a necessity since there is not someone else there to help you with your kids.

VOA: standard.2009.12.04

If there's a group, responsibility to help decreases and this is captured in different ways but the main idea is we all think someone else will help so we don't. There's a diffusion.

如果是一群人，帮助的责任就会分散变小,这体现在多个方面,但最主要的想法就是我们都认为别人会帮助,所以我们就不帮助了，责任被分散了。

耶鲁公开课 - 心理学导论课程节选

Hence, selfish genes will lead to altruistic animals because, to the extent that evolution operates at the level of the genes, there's no hard and fast distinction between your own body and someone else's body.

所以，自私基因会导致利他行为，从这个意义上说,进化在基因层面进行，你自己的身体和别人的身体,没有严格差别。

耶鲁公开课 - 心理学导论课程节选

Now, there's someone else here tonight, born 79 years ago.

CNN: State of the Union Address

And if someone else comes in, there's another crew waiting.

CNN: Chicago's record murder rate: Don't blame guns alone

There's no reason that a book retailer (or someone else) couldn't define the digital reading experience and create a commercial proposition around reading.

FORBES: Magazine Article