i don't know what i should do with it.with是什么?

i don't know what i should do with it.with是什么?
i don't know what i should do with it.with是什么?

i don't know what i should do with it.with是什么?
接上面的补充,此句为倒装句 全句的意思为
对于此事我不知道该如何是好.

介词，
意思是对，关于
表示对象