How is と used in these sentences?


I have some sentences that involve the usage of と that I still don't
understand:

[1.](https://japanese.stackexchange.com/questions/51660/can-
particle-%E3%81%A8-be-used-with-%E5%88%86%E3%81%8B%E3%82%8B/51678) This is
from another user's post

> 私はあなたがいつも忙しい **と** 分かっています。

[2.](https://japanese.stackexchange.com/questions/57022/why-
is-%E3%81%84%E3%81%A4%E3%82%82-used-in-this-sentence) My previous question

> いつも **と** 変えてたまに外で食事しよう。

* * *

At the very basic level, this
[post](https://japanese.stackexchange.com/questions/15363/confusion-with-
japanese-particle-%E3%81%A8-in-its-multiple-uses) pretty much sums up what I
understand about と. I added a few more usages based on what I learnt so far.

  * Quotation or defining particle

> e.g. [X]は日本語でなん **と** 言いますか？How do you say [X] in Japanese?
>
> e.g. 日本語は難しい **と** 思います。(I) think Japanese is difficult.
>
> e.g. 彼は明日来る **と** 言った｡ He said that he will come tomorrow.

  * Conditional particle

> e.g. 彼は暇だ **と** いつもゲームをしているの。If he is free, he always plays games.

  * List of things

> e.g. ナイフ **と** フォークでステーキを食べた。(I) ate steak with a knife and fork.

  * With/Partner of interaction/Accompaniment

> e.g. 友達 **と** 映画に行った｡(I) went to watch a movie with my friend.
>
> e.g. 父 **と** 似ている。(I) resemble my father.

  * Objects of similarity/difference

> e.g. 私の意見は彼の意見 **と** 異なる。My opinion is different from everyone.
>
> e.g. いつも **と** 同じ電車です。(It) is the same train as usual.

  * Sound/Onomatopoeia

> e.g. 星がきらきら **と** 輝いている｡The stars are twinkling.

I understand there are many more uses of と that I did not include in the list
and that I may not be aware of.

* * *

I have trouble connecting both of the sentences above into one of the listed
categories.

But if I had to guess, と under sentence 1 is used as a Quotation or defining
particle? Such as the second example 日本語は難しいと思います。

And for sentence 2, I see it used like いつもと同じ電車です under Objects of
similarity/difference.

But I'm confused here because 変える is not a "similarity" but a "change from
usual". However, I might have a misconception that と is not just used for
objects of similarity or differences in this particular case.

Can someone explain how と is used in each of the sentences above? I would
appreciate similar examples like ones provided above to help me understand how
と is used in these cases, and I'm really thankful to anyone who can help clear
up my confusion with this particle.




As for your first sentence, you're right that the と is a quotative particle.  
It's often used with a verb that introduces one's utterance or thought, e.g.
言う, 思う, 感じる, 知る, 分かる, 話す, etc.

A few examples:

> 嫌だ **と言う**  
>  危ない **と感じる**  
>  やめよう **と思った**  
>  痛い **と** 顔をしかめる (「言って」「思って」 etc. are occasionally left out)  
>  これが最後 **と** 別れを惜しむ  
>  (examples above taken from 明鏡国語辞典)  
>  正しい **という** 結論に達する  
>  (from
> [デジタル大辞泉](https://dictionary.goo.ne.jp/jn/154670/meaning/m0u/%E3%81%A8/))

* * *

As for your second sentence, you're right again that the と indicates
「比較・類別の際に照合される相手」(明鏡国語辞典) ,
「比較の基準」([デジタル大辞泉](https://dictionary.goo.ne.jp/jn/154670/meaning/m0u/%E3%81%A8/)),
or "Object of Similarity/Difference" in your list.  
The と is often used with a verb or adjective that expresses difference,
change, similarity, identity (sameness), or comparison, e.g. 同じ, 違う, 異なる, 似る,
比べる, etc. and it functions like "(same) as..." "(different/differentiate)
from..." "(similar) to..." "(compare) with...". In your example, ～と変える is used
to mean "change from...". (～と変える can also mean "change into~~" (≂～に変える)
depending on context, and the と here indicates 動作の結果. By the way,
～と[代]{か}える/[替]{か}える can mean "exchange for~~/replace with~~", where the と
indicates 動作の対象.)

A few examples:

> あなた **と同じ** 考えだ  
>  以前 **と** は条件が **異なる**  
>  父[子]は子[父] **と似ている**  
>  (examples taken from 明鏡国語辞典)  
>  君の **と** は **比べものにならない**  
>  昔 **と違う**  
>  (from
> [デジタル大辞泉](https://dictionary.goo.ne.jp/jn/154670/meaning/m0u/%E3%81%A8/))

* * *

By the way, the example `父と似ている。(I) resemble my father` is categorized in
`With/Partner of interaction/Accompaniment` in your list, but I think it
should fall under `Objects of similarity/difference`.




As for your first sentence, you're right that the と is a quotative particle.  
It's often used with a verb that introduces one's utterance or thought, e.g.
言う, 思う, 感じる, 知る, 分かる, 話す, etc.

A few examples:

> 嫌だ **と言う**  
>  危ない **と感じる**  
>  やめよう **と思った**  
>  痛い **と** 顔をしかめる (「言って」「思って」 etc. are occasionally left out)  
>  これが最後 **と** 別れを惜しむ  
>  (examples above taken from 明鏡国語辞典)  
>  正しい **という** 結論に達する  
>  (from
> [デジタル大辞泉](https://dictionary.goo.ne.jp/jn/154670/meaning/m0u/%E3%81%A8/))

* * *

As for your second sentence, you're right again that the と indicates
「比較・類別の際に照合される相手」(明鏡国語辞典) ,
「比較の基準」([デジタル大辞泉](https://dictionary.goo.ne.jp/jn/154670/meaning/m0u/%E3%81%A8/)),
or "Object of Similarity/Difference" in your list.  
The と is often used with a verb or adjective that expresses difference,
change, similarity, identity (sameness), or comparison, e.g. 同じ, 違う, 異なる, 似る,
比べる, etc. and it functions like "(same) as..." "(different/differentiate)
from..." "(similar) to..." "(compare) with...". In your example, ～と変える is used
to mean "change from...". (～と変える can also mean "change into~~" (≂～に変える)
depending on context, and the と here indicates 動作の結果. By the way,
～と[代]{か}える/[替]{か}える can mean "exchange for~~/replace with~~", where the と
indicates 動作の対象.)

A few examples:

> あなた **と同じ** 考えだ  
>  以前 **と** は条件が **異なる**  
>  父[子]は子[父] **と似ている**  
>  (examples taken from 明鏡国語辞典)  
>  君の **と** は **比べものにならない**  
>  昔 **と違う**  
>  (from
> [デジタル大辞泉](https://dictionary.goo.ne.jp/jn/154670/meaning/m0u/%E3%81%A8/))

* * *

By the way, the example `父と似ている。(I) resemble my father` is categorized in
`With/Partner of interaction/Accompaniment` in your list, but I think it
should fall under `Objects of similarity/difference`.

