What can I do there?=What can I do in TianJin?

如果是2个单独的句子,只能说句子的结构与形式相同,意思不同哟.What can I do there?中因为用了there,使得地点变成了不确定的,而in TianJin 则是具体的地点.
如果上下文中的句子,两者表达的意思却是相同的.
再问： 那What would I do in there?对吗
再答： there是副词，其意思是“在那里”，介词后面只能加名词、代名词或名词性短语，不可加副词哟。所以，What would I do in there?不对，What would I do there?才是对的。