lose (your) marbles
informal
to start acting in a strange way and forgetting things.
I may be old, but I haven't lost my marbles yet.
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。