“恢复镇定”常见的英文表达有 regain one's composure、recover one's calmness 或 get back one's composure。
regain one's composure： “regain”表示“重新获得、恢复” ，“composure”指“镇定、沉着”，该短语强调重新找回之前失去的镇定状态。例如：After the initial shock, she managed to regain her composure.（在最初的震惊之后，她设法恢复了镇定。 ）
recover one's calmness： “recover”有“恢复、重新获得”之意 ，“calmness”表示“平静、镇定”，此表达侧重于从不安中恢复平静的状态。例如：It took him a few minutes to recover his calmness after the argument.（争吵过后，他花了几分钟才恢复平静。 ）
get back one's composure： “get back”表示“重新获得、找回” ，“composure”依旧是“镇定”的意思，强调再次找回镇定的感觉。例如：He was very nervous at first, but soon got back his composure.（他一开始非常紧张，但很快就恢复了镇定。 ）