YOU SAID:

It's the quiet ones you need to watch out for

INTO JAPANESE

それはあなたが気を付ける必要がある静かなものです

BACK INTO ENGLISH

it's a quiet thing you need to watch out for

INTO JAPANESE

それはあなたが気を付ける必要がある静かなことだ

BACK INTO ENGLISH

it's quiet you need to be careful

INTO JAPANESE

静かに、気をつける必要がある

BACK INTO ENGLISH

You need to be quiet and careful.

INTO JAPANESE

あなたは静かに注意する必要があります。

BACK INTO ENGLISH

You need to be quiet and careful.