in a class by (itself)
the best or only one of its kind.
The High Desert Museum was in a class by itself.
Usage notes: also used in the form in a class by yourself:
Among jazz singers, she was in a class by herself.
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。