Na-adjectives conjugate like nouns using です / ではありません. Basic: Shizuka desu. (It is quiet.) Negative: Shizuka dewa arimasen. (It is not quiet.) Past: Shizuka deshita. (It was quiet.) Neg. past: Shizuka dewa arimasendeshita. (It was not quiet.) Before noun: shizuka ＋ な ＋ noun → shizuka na heya (a quiet room) ✅ Common na-adjectives: shizuka, kirei, nigiyaka, yūmei, benri 💡 「きれい」looks like an i-adjective but is a na-adjective (e.g., kirei na hana = a beautiful flower)