Pecm
abbr. passive electronic countermeasures 被动电子对抗，无源[消极]电子干扰; Preliminary Engineering Change Memorandum 初步工程更改备忘录（美国空军）; processing element control memory 处理单元控制存储器
🗣️ 情景例句
Sure. We've been in business about five years now.
当然。我们创业至今有五年的历史。
In vain.
白忙一场。
Once waves have been generated,
一旦波浪形成，