今天看英语真题的时候发现了这么一句话：

This success, coupled with later research showing that memory itself is not genetically determined, led Ericsson to conclude that the act of memorizing is more of a cognitive exercise than an intuitive one.(2007 Text 1)

这句话中用了一个很奇怪的结构，more of···，一开始我以为是特殊用法，去查词典但是查不到，这句话意思很容易理解，总感觉这个of是画蛇添足多出来的，google了一下，发现这个还真不是什么特殊用法，很多的文章都不会用more表示更加，而是使用more of 。

For the first time on a global scale, being overweight has become more of a health problemthan lack of nutrition.(New Scientists 2012/12/23) Americans are spending more of the oil-price windfall than they realise.(The Economist 2015/10) Nomore of the same, please。(The Economist 2015/11/14) Studies of both animals and humans have shown that sex hormones somehow affects the stress response, causing females under stress to produce more of the trigger chemicals than do males under the same conditions.(2008 Text 1) Knowing what you're good at and doing even more of it creates excellence.(2009 Text 1)

more of 后面大多是名词单数，或者有the，this，that限定的名词和代词，这点与more+名词复数/不可数名词不同。 我的理解是因为more是many/much的比较级，more of a/an+名词表示更多的应该是继承于many a/an+名词的用法(this that也是单数)，具有一种强调的作用，谓语动词也都是单数。 因为变成比较级之后more不能直接接单数名词，因此要加上of。同样地也不能more the+名词，因此要用more of the+名词(不清楚是不是有many the的用法)。 至于其他情况一般是more of的所有格用法，意为···中的更多，很容易理解。

总结

总结一下，对于more+名词的情况，直接加名词的话不需要of，否则的话需要使用more of。

2016.6.27 又在quora上发现一个more of