这里的where是什么成分?能不能换成that?

这里的where引导定语从句:where even people bothered.the worst option,修饰one case .
此处的case作" 情形"讲,where= in the case(在这种情形中),表示模糊的地点,
是一个抽象的地点状语,故用where引导定从.
因此where不能换成that (因为 that 在定从中只能做主语,宾语,不能作状语)
此句中也不能用that来引导同位语从句.
case作"案件,情况"讲时,并且需要对 case作补充说明时,才能用that来引导同位语从句.如:
We are looking into the case that the bank was robbed yesterday.
我们正在调查昨天的银行抢劫案.
I know the case that he used to be in prison .
我知道他过去坐过牢(的情况).
补充知识:
像case 这类表示模糊地点的词,常见的有point,case,age,business,occasion,situation,chair
等.当其作先行词时,且在定从中表示抽象的地点状语时,定从就要用where引导.‍‍‍‍‍‍ 如:
‍We’re just trying to reach a point【where】both sides will sit down together and talk.
I can think of many cases【where】students obviously knew a lot of English words and
expressions but couldn’t write a good essay.
‍‍‍‍