请问这句话why 引导的是什么从句 that is probably why Lily want to kill him

表语从句：
这句话的意思是：
这大概就是为什么Lily 起初想要杀了他（的原因）.
why可以引导一个表示原因的名词性从句,作宾语或着表语.
1、The new book is about how Shenzhou 20 manned spaceship was sent up into space.
how 引导一个名词性从句,作介词about的宾语；
2、He is glad that Li Ming went to see him when he was ill
that引导一个状语从句,表示glad（高兴）的原因.
be+副词+that,就是表语从句.
be+形容词或过去分词,that就引导状语从句.
be+介词,that引导的从句,就做介词的宾语（从句）

系动词后面加的从句就是表语从句。
eg: I am what I am.我就是我。
The fact is that the earth goes round the sun

表语从句。

宾语从句，望采纳