Chinese Language Stack Exchange is a question and answer site for students, teachers, and linguists wanting to discuss the finer points of the Chinese language. It only takes a minute to sign up.
Sign up to join this community
Often, I come across sentences like below, where the subject is missing and the object is placed instead.
证件带了吗？ （Instead of 你带了证件吗？)
I am wondering if there is a name to such grammatical structure, and if there are any conditions to be aware of when I want to use such structure. Thank you!
It's called topic-comment structure and it's ubiquitous in Chinese. It's one of its distinctive grammatical traits.
What is called topic, or theme, is the focus of the sentence and is extracted at the beginning of the sentence, regardless of its grammatical function. This last remark is especially important. The topic isn't necessarily also the grammatical subject of the sentence.
What is called comment, is usually what contains the predicate and provides the additional information about the topic that you want to convey. In wikipedia's words "it's what is being said about the topic".
When the topic is a complex structure, it's often separated from the rest by a comma in writing, and by a brief pause in speech. In writing the comma may disappear for simple topics. But you can add it again to test this:
证件，带了吗？
证件 is the topic, and the grammatical object of the sentence. The two are not mutually exclusive.
（你）带了吗 is the comment, and the grammatical predicate. The actual subject 你 is omitted, as it's understood from the context (supposedly this sentence is being addressed at you).
Other examples where the topic is the object (with and without comma):
饭吃了吗 = Have you eaten already?
别人的中文名字，你一定要记住啊 = Make sure to remember other people's Chinese names!
Maybe I could answer the second question. Native users use these kind of sentences everyday.
It's simple and straightforward but a little impolite to elders, your boss, strangers, etc. Please add 請問 to show your polite.
Make sure the person you are talking to is the person should/could/may know the situation.
e.g.
1
A:車停在哪？
B:在停車場。
2
A:車站怎麼走？
B:直走就到。
3
A:車跑了嗎？
B:還剩五分鐘。
4
A:咖啡泡了嗎？
B:還在泡。
I decide to retract my previous answer and add a new one.
In Chinese Grammar, there is a term called 无标记被动句 (Unmarked passive sentences), which means there is no marker(such as 被，让，把，etc) to indicate the passive voice in the sentence but it's actually passive voice. Your example 证件带了吗 demonstrates this characteristics.
So, 证件 is Subject and 带了吗 is Predicate.
Btw, the topic-comment structure is another way to see it, but 无标记被动句 is the term we are taught in schools for native speakers.
