(just) in the nick of time
at the last possible moment.
A man walking his dog saw her fall into the river and pulled her out just in the nick of time.
英语词组固定搭配大全包含18674条英汉双解词组，基本涵盖了全部常用英文词组、短语的翻译及用法，是英语学习的有利工具。