can someone explain the use of で particle in this sentence: こんなに単純で当たり前なこと


i'm getting confused with the で particle in this sentence. This line belongs
to Keno.

The complete line is: こんなに単純で当たり前なことが 本当は、一番見失いがちだからね.




> 「こんなに単純{たんじゅん} **で** 当{あ}たり前{まえ} **な** ことが
> 本当{ほんとう}は、一番{いちばん}見失{みうしな}いがちだからね。」

First, notice (if you have not) that **_two_** na-adjectives are used to
modify 「こと」 in this sentence -- 「単純な」 and 「当たり前な」 to use their dictionary
forms.

To connect multiple adjectives or verbs in one clause, all except the last one
**_must_** be conjugated into their 連用形{れんようけい} ("continuative form"). Thus it
is **_incorrect_** to say:

> 「単純 **な** 当たり前 **な** こと」 using 「な」 twice

You need to turn the first adjective 「単純 **な** 」 into its 連用形. Its 連用形 is 「単純
**で** 」. Voilà, that is the answer. The **_correct_** phrase is:

> 「単純 **で** 当たり前 **な** こと」

Finally, here is how na-adjective 「単純な」 conjugates.

未然形{みぜんけい} (imperfective form): 単純 **だろ** （う）

連用形{れんようけい} (continuative form): 単純 **だっ** （た）、単純 **で** （ある/ない） and 単純 **に**

終止形{しゅうしけい} (predicative form): 単純 **だ**

連体形{れんたいけい} (attributive form): 単純 **な**

仮定形{かていけい} (hypothetical form): 単純 **なら**

(Unlike with verbs, there is no 命令形{めいれいけい} (imperative form) for adjectives.)

So, the sentence means:

> "Things that are this simple and ordinary are actually the things that we
> most tend to lose sight of."

It was on purpose that I have written a much longer answer than I should have
because I keep seeing questions regarding adjective and verb conjugations
asked when the questioners themselves do not even seem to be aware that they
are conjugation questions.




> 「こんなに単純{たんじゅん} **で** 当{あ}たり前{まえ} **な** ことが
> 本当{ほんとう}は、一番{いちばん}見失{みうしな}いがちだからね。」

First, notice (if you have not) that **_two_** na-adjectives are used to
modify 「こと」 in this sentence -- 「単純な」 and 「当たり前な」 to use their dictionary
forms.

To connect multiple adjectives or verbs in one clause, all except the last one
**_must_** be conjugated into their 連用形{れんようけい} ("continuative form"). Thus it
is **_incorrect_** to say:

> 「単純 **な** 当たり前 **な** こと」 using 「な」 twice

You need to turn the first adjective 「単純 **な** 」 into its 連用形. Its 連用形 is 「単純
**で** 」. Voilà, that is the answer. The **_correct_** phrase is:

> 「単純 **で** 当たり前 **な** こと」

Finally, here is how na-adjective 「単純な」 conjugates.

未然形{みぜんけい} (imperfective form): 単純 **だろ** （う）

連用形{れんようけい} (continuative form): 単純 **だっ** （た）、単純 **で** （ある/ない） and 単純 **に**

終止形{しゅうしけい} (predicative form): 単純 **だ**

連体形{れんたいけい} (attributive form): 単純 **な**

仮定形{かていけい} (hypothetical form): 単純 **なら**

(Unlike with verbs, there is no 命令形{めいれいけい} (imperative form) for adjectives.)

So, the sentence means:

> "Things that are this simple and ordinary are actually the things that we
> most tend to lose sight of."

It was on purpose that I have written a much longer answer than I should have
because I keep seeing questions regarding adjective and verb conjugations
asked when the questioners themselves do not even seem to be aware that they
are conjugation questions.

