Interest is as vital to learning as the ability to understand, even more so. 

【翻译】对学习来说，兴趣和理解能力一样重要，甚至（比理解能力）更为重要。

【结构分析】本句含有两种比较结构：as...as...和more + adj. + than

1. as...as...结构中，相比较的两个事物是Interest和the ability，to understand作the ability的定语。而to learning是介词短语，意为“对学习而言”。为了理解方便，现在提到句首：

To learning, interest is as vital as the ability to understand, even more so. 

2. even more so = even more vital （so代替vital），后面承前省略了than the ability to understand。补充完整就是：even more vital than the ability to understand。

更多例句：

If the portraits were confusing, the dentures were even more so.  如果肖像令人感到困惑，则假牙更是如此。
Programs are expensive, and even more so if you have to keep altering them.  软件很贵，如果老是更换，那就更贵了。
A marriage without love is a misfortune. But a marriage without a dwelling is even more so.  没有爱情的婚姻是不幸的,而没有房子的婚姻则更不幸。