that用于关系副词时与where可以替换吗?

that是关系代词,不是关系副词!that可以担任主语和宾语,where是关系副词,不能互换!
上面句子中的where代替的是there.
如果把含定语从句的句子还原成两句,应该是：
There was my purse in the back of the seat.
I cuoldn't see it there before.
Hope this helps.