门口的保安每天都会跟我们打招呼。

Ménkǒu de bǎo'ān měitiān dōu huì gēn wǒmen dǎzhāohu.

The security guard at the entrance greets us every day.

学校请了专业的保安公司来负责校园安全。

Xuéxiào qǐng le zhuānyè de bǎo'ān gōngsī lái fùzé xiàoyuán ānquán.

The school hired a professional security company to be responsible for campus safety.

图书馆门口有两名保安检查学生证。

Túshūguǎn ménkǒu yǒu liǎng míng bǎo'ān jiǎnchá xuéshēngzhèng.

There are two security guards at the library entrance checking student IDs.