Dāng tán dào sònghuò, ānzhuāng, zèngpǐn, tuìhuàn zhèxiē xìjié shí, zuìhǎo ràng diànyuán xiě zài dānzi shàng

当谈到送货、安装、赠品、退换这些细节时，最好让店员写在单子上。

When discussing details like delivery, installation, gifts, or returns, it's best to have the clerk write them down on the receipt.