[na-adjectives]: genkina(healthy, sound, cheerful), shizukana(quiet), shinsetsuna(kind), benrina(convenient, useful), kireina(beautiful, clean),etc.
[Noun wa <na-adjective> + Noun + desu] : 1) kare wa shinsetsuna hito desu.(He is a kind person.) 2) kore wa totemo benrina jisho desu.(This is a very useful dictionary.)
[Noun wa <na-adjectve> + desu] : 1) watasshi no sensei wa shinsetsu desu.( My teacher is kind.) 2) Sakura wa kirei desu.(Cherry blossoms are beautiful.)