Okay, those three make me very confused. To my understanding だいぶ is used when
it´s more than what you expected. 大体 should be more or less, but then where
comes 大部分? And is 大体 a lesser percentage than ほとんど?

Thank you very much for your help.
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2016-03-10T20:00:33.277
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2016-04-05T04:22:33.667
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question
word-choice nuances adverbs
What exactly are the differences between 大体, だいぶ and 大部分
だいぶ means "rather"and it is used as adjective and adverb.

大体、ほとんど means "almost" and they are used as noun and adverb.

大部分 means "for the most part" and "mostly", it is used as noun but sometimes
used adverbially.

You choose these adverbs according to the situation.

For example, 私は図書館の本をだいぶ借りた(I rather borrowed books of a library).

私は図書館の本を大体(ほとんど)借りた(I almost borrowed books of a library).

私は図書館の本を大部分借りた(I mostly borrowed books of a library).

大体、ほとんど, 大部分 mean almost same.
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2016-03-12T11:38:05.963
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2016-03-12T11:38:05.963
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answer
* **だいぶ（大分）**  
An adverb meaning "becoming more advanced (= grown, progressed, lapsed
away...) than before", or if lacks the starting point it means "...than you/I
expect", or simply "considerably". It doesn't tell anything about percentage.

Synonyms are 相当, かなり, ずいぶん etc.

> 白髪が（○だいぶ／×大体／×大部分）増えてきた。

  * **だいたい（大体）**  
An adverb but sometimes used noun-like, "almost all/complete", "almost every
time/aspect" or "overall". You're right about "more or less" as in "more or
less finished".

The difference with **ほとんど** is that:

    * ほとんど is slightly closer to perfect in amount (I think)
    * だいたい lacks the use of "almost _something_ " 

> 彼は（○ほとんど／×だいたい）英雄だ。

    * ほとんど qualifying a noun means "nearly _noun_ " while だいたい is "approximately _noun_ " 

> 70%ということは（×ほとんど／○だいたい）3分の1だ。

Synonyms are おおむね, あらかた etc.

> 私は（×だいぶ／○だいたい／×大部分）いつも居間にいる。

  * **大部分**  
As you read, "(for) the great(est) part"; mostly noun, but also adverb. You
can use this word only for something whose percentage is clear rather than
subjective impression, and must tell "part of _what_ (noun)" (and conversely,
the other two are not going well with "of something").

> 彼女は人生の（×だいぶ／×だいたい／○大部分）を芸能界で過ごした。
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2016-03-13T08:15:29.110
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