in reserve
成語所屬單字reserve
in reserve — 慣用語
1. kept ready and not used yet, so that it can be brought out later if a problem ap
1.慣用語
釋義
備而不用；保留備用
kept ready and not used yet, so that it can be brought out later if a problem appears or if extra help is needed.
例句
Élise always keeps a clean shirt in reserve in her desk drawer for surprise meetings.
The general held two battalions in reserve behind the front line.