shifting sands
不稳定的环境或情况，经常发生变化
书面/口语·描述不稳定局势
英文释义
constantly changing or uncertain situation
例句
The job market is like shifting sands; you never know what skills will be needed next.
典故来源
源自沙漠中随风移动的沙丘，比喻环境或情况不断变化、不稳定。