Subject + 要 + 小心
小心 (xiǎoxīn) is a verb meaning "to be careful" or "to watch out." It is often used as a warning or reminder to exercise caution. For example, 我们要小心 means "we need to be careful."
路上很滑,你走路要小心。
Lù shang hěn huá, nǐ zǒulù yào xiǎoxīn.
The road is slippery; be careful when you walk.
小心别把杯子打碎了。
Xiǎoxīn bié bǎ bēizi dǎ suì le.
Be careful not to break the cup.
晚上一个人出门要小心一点。
Wǎnshang yí gè rén chūmén yào xiǎoxīn yìdiǎn.
Be a little more careful when going out alone at night.