She demands to know whose（充当表语） the child was. I wonder whose （充当定语）house that is.

She demands to know whose（充当表语） the child was. I wonder whose （充当定语）house that is.

第一句，whose the child was 是know 的宾语，正常语序 the child was whose, (whose 为表语）
第二句，whose house that is 是wonder 的宾语，正常语序that is whose house(whose 是house 的定语）

这个判断和句子成分有关，把第一句换成正常语序是She demands to know the child was whose.把第二句换成正常语序是I wonder that is whose house.这样来看因为第一句中的结构为主系表，所以whose作表语，第二句中也是主系表不过表语是house，而此时whose只是修饰它的定语。不要从归属角度判断，容易混，以后遇到此类问题直接变成陈述语序即可。真心希望对你有帮助，不懂随时问。

whose(只用作定语)“whose”表示谁（可以为人也可以为物）的（东西）例：

A child whose parents are dead is called an orphan.双亲都死了的孩子叫做孤儿。（“whose parents”表示那个孩子的双亲）

He lives in a room whose window faces south.他住的那个房子的窗户是朝南的。（“whose”表示那个房子的窗户）

Whose 用来指人或物，(只用作定语, 若指物，它还可以同of which互换）, 例如：

They rushed over to help the man whose car had broken down.
那人车坏了，大家都跑过去帮忙。

Please pass me the book whose (of which) cover is green. 请递给我那本绿皮的书。

表语是在系动词如is are am remain stay 之后的