真的那扇門
這一組就是畫面本身，不是比喻。其他用法都要先看得見這扇門，才有東西可以借。
noun · B1
A door in the entrance of a large building, made of several parts joined in the middle, that turns around as people push through it, so people can go in and come out at the same time.
旋轉門
核心畫面
One way to hold this word is to stand at the door itself: several panels joined to a pole in the middle, turning all day. Nobody opens it and nobody closes it. You push, it carries you round, and you come out on the other side. Because it never stops, one person can be going in at the very moment another is coming out — and if you do not step off, the same door brings you back to where you started. Every other use of the phrase borrows one part of that picture: the steady stream of people, or the coming back round.
這個詞可以想成一扇一直在轉的門：幾片門板連在中間的軸上，沒有人去開它，也沒有人去關它。你推一下，它就帶著你繞過去，你…更多收起
這個詞可以想成一扇一直在轉的門：幾片門板連在中間的軸上，沒有人去開它，也沒有人去關它。你推一下，它就帶著你繞過去，你從另一邊走出來。因為它不會停，所以有人進、有人出可以同時發生；而如果你沒有在出口踏出去，同一扇門就會把你帶回原來的位置。後面幾個比喻用法，都是各拿走這個畫面的一部分——有的拿「人流一直換」，有的拿「又繞回來」。Three branches
位子上的人一直換
從門的畫面裡拿走「人流」：門一直轉，人就一個接一個出去、一個接一個進來，沒有人停在裡面。把這個放到一份工作或一個組織上，就是留不住人。
noun · C1
A job, team, or organization that people keep leaving and being replaced in, so one new person after another fills the same place and almost nobody stays long.
人事一直換
同一批人又繞回來
從門的畫面裡拿走另一半：門是圓的，走出去的那扇門，也是走回來的那扇門。所以這一組講的不是換人，而是同一個人再度出現。
noun · C1
A situation in which people who leave a job or place keep coming back to it later in a different role, for example officials who leave a government office and return as paid representatives of the companies that office deals with.
旋轉門現象