What's the matter?是倒装句吗?是的话,其正常语序是……?

不是倒装句,而是特殊疑问句.不过,本句的主语正好是疑问词"what",因此,在宾语从句中不用改变语序.如：I don't know what is the matter with him.
所谓的倒装句是陈述句用了疑问句的语序：如：Only in this way can we learn English well. [本句中的can we就属于倒装句结构.]