That's especially true of booming fields that are challenging for workers.
问题描述：
That's especially true of booming fields that are challenging for workers.
That's especially true of booming fields that are challenging for workers
这句话有什么句子成分?怎么理解
答
急速发展的领域真可谓是炙手可热,对普通员工来说确是个挑战
That's （主语+系动词）especially true of booming fields（表语） that are challenging for workers（定语从句）