N4 — outside your level filter
Is said whole, with nothing composed onto it and takes no だ／です, so there are no forms to conjugate.
そうだ
soudaoh, I know!N4expression
Example sentences2
あ、そうだ、明日は病院の予約がありました。
a, souda, ashita wa byouin no yoyaku ga arimashita.
Oh, that's right, I had a hospital appointment tomorrow. neutral
そうだ!今度みんなでバーベキューしようよ。
souda! kondo minna de baabekyuu shiyou yo.
Oh, I know! Let's all have a barbecue sometime. casual