这家超市在每个收银台都安装了新的POS系统。

The supermarket installed new ___POS systems at every checkout counter.

别发那个表情包，混蛋！

Don't send that meme, ___POS!

在学习英语时，理解每个单词的词性很重要。

When learning English, it's important to understand the ___POS of each word.