あなたはもっと注意しなければならない。

あなたはもっと注意しなければならない。

You need to be more careful.

あなたはもっと注意(ちゅうい)しなければならない。

Anata wa motto chūishinakerebanaranai.

貴方 (あなた)

you (referring to someone of equal or lower status); dear (what a wife calls a husband)

は (は)

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

もっと (もっと)

(some) more; even more; longer; further

注意 (ちゅうい)

caution; being careful; attention (heed); warning; advice

Readings: チュウ、そそ.ぐ、さ.す、つ.ぐ

Meanings: pour, irrigate, shed (tears), flow into, concentrate on, notes, comment, annotate

Reading: イ

Meanings: idea, mind, heart, taste, thought, desire, care, liking