What is the most simple thing that most people know that you had to explain to someone that did not know it?
有什么大多数人都知道的最简单的事你还要对不懂的人解释？
获得5.1k好评的回答@Manuela Cabrera：
That women have periods no matter what country they're from.
无论哪个国家的女人都有月经。
Yes.
是的。
Someone actually didn't know this. And no, it wasn't a 5-year-old boy. It came from a supposedly well-educated female classmate, that was 16 years old at that time.
有人就不懂，当然这个人不是5岁的小男孩。这个问题来自一个应该受过良好教育的女同学，当时她16岁。
She was hosting a German exchange student and couldn't understand why she'd laughed so much at her question: “Do girls have periods in Germany too?”
她家里有一个德国交换生，而且她不明白为什么对方听到她的问题“德国女孩也有月经吗？”会笑得前仰后合。
I had to explain to her why the girl had thought she was kidding and that geography wasn't a period determining factor.
我就跟她解释为什么对方以为她在开玩笑，而且地域也不是决定月经时间的因素。
获得14.3k好评的回答@John Geare：
I couldn’t make this up.
这个事真不是我能编出来的。
A worker in my office made a copy of a document before faxing the document.
我办公室里的一个职员发传真之前先把文件复制一份。
She was assuming that the original physical document itself was sent over the phone lines and she would therefore need to copy the original before sending it because the original would disappear from our fax, and reappear at the receiving fax.
她以为源文件能从电话线发出去，会从我们的传真机里消失，然后出现在接受文件的传真机里，所以她发传真之前需要复制一份。
But didn’t she notice the original when it reappeared in the output tray? No, she didn’t. She stacked the originals in the feeder tray, punched in the number and walked away.
但难道源文件再次出现在接纸盘上时她没看见吗？她没看见。她把源文件放在送稿托架上拨完号就走了。
Over the course of a week, or so, other workers noticed that the output tray was filling up with previously sent faxes. As a courtesy, they scooped them up and filed them away, assuming it was just an oversight or the sender was called away. Until someone noticed that the file folder had a copy of the original already in it.
一周左右的时间里其他职员注意到接纸盘上堆满了发完传真的文件。大家出于礼貌把文件收起来堆在一边，以为只是有人一时疏忽或者发传真时被叫走了。直到有人发现文件夹里还有一份源文件的复印件。
That’s when the matter was brought to my attention. With a little eaves-dropping, we finally figured out who our very cautious sender was. That’s when I sent “the memo.”
我这时才注意到这件事。简单窃听之后我们最终知道了这个非常谨慎的发传真的人是谁，然后我发了一个“备忘录”。
Dear Everyone:
亲爱的各位：
A quick housekeeping item for you. When sending a fax, please remember to retrieve the original document from the output bin so you may return it to the file. It is no longer necessary to make a file copy of the original. Thank you for your attention.
快速管家消息：发传真时请记得从出纸槽拿走源文件以便放回文件夹，没必要复制源文件。谢谢配合。
That did the trick. A few days later, the guilty worker appeared in my office to identify herself, express regret at her “stupidity,” and thank me for not having called her out specifically.
这招奏效了。几天以后，那个内疚的职员来我办公室承认是她所为，而且对自己的“愚蠢行为”表示很后悔，还感谢我没有特别点她的名字。
All’s well that end well.
皆大欢喜。
（翻译：菲菲）