the situation in which you are as ready as possible to perform a task you have been preparing for

The whole school was at action stations for the inspectors' visit. 全校都做好了准备迎接督察的到来。

used to tell people to get ready immediately to do the particular jobs that they have been given to do

Right, everyone - action stations! We're starting in three minutes. 好了，全体注意，各就各位，三分钟后开始！