知会

wǒ men yīng gāi xiān zhī hui tā yī shēng

我们应该先知会他一声。

We should notify him first.

zhī hui tā yī jù shuō wǒ huí lái le

知会他一句，说我回来了。

Please go and tell him that I've come back.

zào fǎng jǐng jú zhě yīng zhī hui zhí bān jǐng zhǎng

造访警局者应知会值班警长。

Visitors to the police station should report to the duty sergeant.