主语和谓语之间什么情况下有逗号?如这个句子

此句,主语是个从句,所以中间加了逗号.
如果主语和谓语之间插入其他的插入语（独立成分,状语,同位语）,或者从句,也用逗号分开,例：
The hero,however,is still unknown by the people here.
The fire,although it had been burning for several days,was still blazing fiercely.
Alice,my good friend,is now studying in China.

有两个谓语，容易混淆的情况下加逗号。

由于是定向问题，在此做一回答。
Who neglects learning in his youth, loses the past and is dead for the future.
这句句子我也觉得这个逗号有点超乎常规，只是把主语从句分开了，后面接了两个谓语部分（ loses ... and is dead ... .。
查阅语法书并思考后，可能是主语为从句，显得太...