有主语从句吗But you have to know the reason why she is smart is be

冒犯地指出一点儿小错误：
这是哪位大神写的句子,the reason is because……这种搭配根本不存在（原因是因为……呵呵,显然是个病句）
改为But you have to know the reason why she is smart is that she always picks other people's brains 就没什么问题了
意思是“但是你必须要知道她聪明是因为她总是套用别人的思路
在分析一下句子成分：
why she is smart 做the reason 的定语,是定语从句
整个儿the reason（why she is smart）is that she always picks other people's brains是know 的宾语从句,省略了引导词that
在宾语从句中又有一个表语从句,即that she always picks other people's brains 做is 的表语从句
确没有主语从句