Can 主に modify a 体言?


Is [主]{おも}に one of 副詞 that can modify 体言? It seems to be used this way often,
like:

>   1. 与るとは [主]{おも}に目上から、好意の表れとしてあることを受ける。
>
>   2. アメリカでは **主** に経済学を学んだ. In America, he studied mainly economics.
>
>

(random dictionary examples)

But it's not on [this](http://www.weblio.jp/parts-of-
speech/%E5%89%AF%E8%A9%9E%28%E7%A8%8B%E5%BA%A6%29_1) list (主として is though), is
it still a 程度の副詞?




主に is an adverb which indicate dimension like mainly, mostly.

Dictionaries explain 主に means 主として,大部分,ほとんど.

I think adverbs modify only verbs and adjective at first but there are some
adverbs which modify nouns and adverb.

主に can modify noun like your example, 主に modify 経済学(noun) and 学んだ(verb) in
アメリカでは主に経済学を学んだ.

And もっと can modify adverb like もっと modify ゆっくり(adverb) in もっとゆっくり話せ.

In addition, there are some dimension verbs which modify both noun and verb at
a time like 少し. For example. 少し in 彼は少し右に動いた modify 右(noun) and 動いた(verb) like
少し右に and 少し動いた.




In short: **no, 主に can't modify 体言{たいげん} directly.** More detail:

## 主{おも}に and 用言{ようげん}

主{おも}に is a 副詞 (adverb), and thus it modifies 用言{ようげん} (verbs and adjectives).

In your example, it might look like 主に is modifying a noun, since the very
next word is a noun: アメリカでは **主に** **経済学** を学んだ。 However, the 主に, as an
adverb, is actually modifying the verb at the end: アメリカでは **主に** 経済学を **学んだ**
。 The sentence states that someone _studied_ , and it qualifies that action by
also stating the this person _**mainly** studied_ economics.

## 主{おも}な and 体言{たいげん}

There is a usage of 主{おも} that can modify a 体言 directly: it also takes な, much
like any other _-na_ adjective. So we could say アメリカでは **主な学問** は経済学でした。 →
_"In America, (my? the?) **main study subject** was economics."_

