taisetsuna tomodachi to kenka o suru to, kanashii desu.

to be

Breakdown of taisetsuna tomodachi to kenka o suru to, kanashii desu.

• 友とも達だち: friend
• と: companion particle
• と: conditional particle

Questions & Answers about taisetsuna tomodachi to kenka o suru to, kanashii desu.

What does 大切な mean here, and why does it have な on it?

大切な (たいせつな) is an adjective meaning important / precious / special.

Japanese has two main kinds of adjectives:

• い-adjectives: end in い, e.g. たかい (tall), さむい (cold)
  
  • Before a noun: たかい ビル (a tall building)
• な-adjectives: take な before a noun, e.g. きれいな, ゆうめいな, 大切な
  • Before a noun: 大切な 友達 (an important/precious friend)
  • On their own with です: 友達は 大切です (Friends are important.)

So 大切な is a な-adjective, and な is needed when it directly modifies a noun like 友達.

Why is it 大切な友達 and not 大切友達 or 大切の友達?

You can’t say 大切友達 because 大切 is not a noun here; it’s a な-adjective, and な-adjectives need な before a noun.

You also don’t say 大切の友達 because の is used after nouns, but 大切 is functioning as an adjective, not as a noun, in this sentence.

So the correct patterns are:

• Before a noun: 大切な 友達
• As a predicate: 友達は 大切です。

大切の友達 is ungrammatical in standard Japanese.