xiānsheng, qǐng dài yǒuxiàozhèngjiàn.

Sir, please bring valid identification.

Breakdown of xiānsheng, qǐng dài yǒuxiàozhèngjiàn.

• 请qǐng: to ask (politely)
• 带dài: to bring
• 有效证件yǒuxiàozhèngjiàn: valid identification

Questions & Answers about xiānsheng, qǐng dài yǒuxiàozhèngjiàn.

What does 先生 mean here? Is it Mr. or sir?

Here 先生 means sir when directly addressing a man.

In Chinese, 先生 can mean:

• Mr. + surname, as in 王先生 = Mr. Wang
• sir, when speaking politely to a man whose name you may not know

In this sentence, it appears by itself at the beginning, so it functions like direct address: Sir, ...

Why is there a comma after 先生?

The comma shows that 先生 is being used as a form of address, separate from the rest of the sentence.

So the structure is basically:

• 先生， = Sir,
• 请带有效证件。 = please bring valid identification.

This is similar to English punctuation in Sir, please bring valid ID.

What does 请 mean here?