如何剖析what is left of their business 语法成分和含义呢？

They are fighting to save what is left of their business. 他们在拼命抢救他们仅余的业务。

这里疑问是： 如何剖析what is left of their business 语法成分和含义呢？

是what of their business is left 如此的语序吗？

They are fighting to save what is left of their business.

划线部分为名词性从句，作 save 的宾语。

of their business 作 what 的定语，被谓语动词 is left 分隔。

又如：

His eyes stare at what is left of the brothers dinner on the table.（他的双眼注视着兄弟两个饭桌上的残羹剩饭）。

这是美国著名作家马克·吐温名作The Million Pound Bank Note上的一个句子。