What is the difference between asking a question using 是不是 and 吗?

For example, what's the difference between these 2 questions:



  • 1
    There's no difference Commented May 22, 2019 at 0:30
  • 1
    "There's no difference" is almost never the right answer when it comes to languages. :) A teacher might say that for pedagogical reasons (i.e. "there's no difference that's worth going into detail about her and now"), but such assumptions are a bit dangerous when questions are asked without context as is the case here.
    – Olle Linge
    Commented Aug 8, 2021 at 6:18
  • The main difference between 是不是 and 吗 is that 是不是 can be used outside of questions, like 我不知道他是不是中国人 and 无论她是不是对的,你最好道歉.
    – Becky 李蓓
    Commented Jun 11, 2022 at 1:26

6 Answers 6


is pretty much like a question mark (?).

  • 你吃午餐了 -> You had your lunch.
  • 你吃午餐了 -> You had your lunch?
  • 你是中国人 -> You are a Chinese.
  • 你是中国人 -> Are you a Chinese?


Google doesn't has a good translation for it, but it basically means yes(是) or no(不是), is(是) or isn't(不是).

  • 中国人 -> You are a Chinese.
  • 不是中国人 -> You aren't a Chinese.
  • 是不是中国人 -> You are a Chinese or you aren't a Chinese -> Are you a Chinese?

You are a Chinese or you aren't a Chinese is rather weird in a normal sentence, because this is directly convert from Chinese to English, in fact it is just a question like Are you a Chinese?.

Additional reading

否 = 不是

Update on 08-August-2021:

Below is wrong because 是不是 can be followed by nominal but 是否 cannot. Thank @GiuseppeRomanazzi for providing the reference.

Instead of 是不是, one can also use 是否, just replace 不是 by .

  • 是否中国人? -> You are a Chinese or you aren't a Chinese -> Are you a Chinese?~
  • 2
    “你是否中国人?” isn't a correct sentence. We should say “你是否是中国人?” instead.
    – dan
    Commented May 29, 2019 at 9:16
  • nope, adding an additional "是" after "是否" would be a totally redundant and no one will use in this way... could be verified this by simply find a sentence that uses "是否" from Google...
    – ch33hau
    Commented May 29, 2019 at 10:09
  • Ch33hau, what @dan said is right, "你是否中国人?" is not correct. According to 《现代汉语八百词》page 503, quote: "注意: ‘是不是’后面可带名词性成分,‘是否’不能。是不是他?| *是否他?" My suggestion: Google can be very useful, but in no way is an authoritative source. It can just help you find everything, both the best and the worst. Commented Jul 26, 2021 at 10:12
  • Thank you so much @GiuseppeRomanazzi, yes you and dan are right. I will correct my answer later.
    – ch33hau
    Commented Aug 7, 2021 at 22:01

There is an important difference when you actually say these two sentences.

"你是中国人吗?" means "Are you a Chinese?"
Why do I ask that? Because "you" behaves or looks like a Chinese, but I am not quite sure (for example, "you" can be a Korean or Japanese).

"你是不是中国人?" means "Are you a Chinese or not?" or "Aren't you a Chinese?"
Why do I ask that? Because "you" is a Chinese, but behaves or looks quite different from a normal Chinese, often in a bad way.

The second sentence is often said with an emphasis on "是不是" to show the emotion. However, even you just write them down, the second one is more emotional. In China, because of the 20th centery history, the second one sometimes has some connection with "叛国" (treason), please be aware of it.

But if you are talking about something less sensitive, e.g. 这是苹果吗? vs. 这是不是苹果? Using the first sentence unless you urge to know the answer.

Generally, "X不X" or "X不XY" has stronger feeling than "吗?" especially "X" is a word with the meaning of certainty (是be有have) instead of probability(可以may).


In most instances there won't be a big difference but 吗 is usually a softer tone for a question.


你是不是中国人? Please note, sometimes, this style is used in following case, you know he is Chinese, the question you asked in order to create a dramatic effect or to make a point rather than to get an answer.


generally speaking the position of 是不是 in a sentence is not fixed, cf."实用汉语语法":值得注意的是,由"是不是"组成的正反形式可以移动位置,例如:是不是我这孩子平时的举动有点叫人说闲话?(曹愚)->我这孩子是不是平时的举动有点叫人说闲话?->我这孩子平时的举动是不是有点叫人说闲话?->我这孩子平时的举动有点叫人说闲话,是不是? 随着"是不是"的移动,疑问焦点也相应移动---疑问焦点落在"是不是"后头最靠近的成分上。Instead of 你是不是中国人? 是不是你是中国人? 你是中国人,是不是? would seem possible (although somewhat verbose)


It's not necessary to add an extra 吗 or 呢 after an alternative question in modern Chinese.

You are (or) not are Chinese?
Are you Chinese (or not)?

You eat (or) not to eat?
Do you want to eat (or not)?

You go (or) not to go?
Do you want to go (or not)?

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