as...as比较句中的省略问题

在有道例句中有一句如此的话：

Much emphasis is put on how to spend as much time if not more studying by themselves as being taught.

请问这句话中if not more studying by themselves是如何省略的？

spend as much time, if not more, studying by themselves as being taught
应该加逗号隔开，就了解了。本句涉及两个问题：
1. as...as... 一样多。
2. spend time doing 花浪费时间间做某事。

把这两种结构合理地柔和在一块，就是：spend as much time doing A as doing B.

句子类比：
Jim plays football as well as, if not better than, Mike. 吉姆踢球假如不是比迈克踢得更好，至少也是一样好。
She sings as well as, if not better than, her sister.
她唱歌假如不比她姐姐好，至少也跟她姐姐一样。
假如不省略，则很啰嗦，重复不少成分。即：
She sings as well as her sister if she does not sing better than her sister.