定语从句中用who不需要that的问题

当先行词指人并含有较长的后置定语或在被分割的定语从句中，宜用who不需要that引导定语从句。

The boy was crying hard who lost his way while looking for his mother.

这里是有后置定语，还是有被分割的定语从句呢？假如有，在哪儿？

The boy was crying hard who lost his way while ;">这里是有后置定语，还是有被分割的定语从句呢？假如有，在哪儿？

以上是分隔式定语从句，定语从句被主句谓语分隔开来，即先行词the boy 与定语从句之间被主句谓语“was crying hard”分隔

以上黑体字是“定语从句”The boy who lost his way while looking for his mother.关系代词who代替先行词the boy，并在定语从句作主语成分。