When to use 是吗 vs 是不是

[Jhorra]

I'm fairly new to learning and I'm mostly teaching myself with various resources, so I apologize if this is a dumb question.

 

I've seen both types of question used.  Is this a case where you can use either, or is there a place where one is more appropriate?

 

I'm using 是 but I've seen this used with lots of verbs, so I'm asking as a general question, not specifically in regards to this verb.

[Tiana]

Mostly they're interchangeable, but in some rare specific cases, only one or other is acceptable.

[arreke]

"是吗" is usually used at the end of the sentence, so is "是不是"

In this case they are interchangeable

 

https://www.youtube.com/watch?v=kYW_2fIZhLE

[arreke]

But sometimes you can put "是不是" in the middle of the sentence 

In this case they are not interchangeable

 

https://www.youtube.com/watch?v=V3Ty85pvy9U

[Vildhjerp]

When you include V不V within your question, you're presenting both possible responses to your question and requesting the person you're asking to go one way or the other. With V...吗, you're providing a declarative statement (followed by a 吗) and requesting the person you're asking to either agree or disagree with your proposal. When using both of these methods, you're position on the information is neutral. Like Tiana and arreke explain, when used this way, they are practically the same.

 

你认不认识他? - Do you know him? (I have no idea whether you know him or not)

你认识他吗? - You know him? (same as above)

他是不是从中国来的? - Is he from China? (I'm not sure if he's from China or not)

他是从中国来的吗? - He's from China? (same as above)

 

However, when not included within your question, but rather, attached to the very end of a statement as a question tag, you're position is no longer neutral. You select the response you believe to be correct or expect to be true, and add the tag as an indicator that you aren't necessarily certain, but make the implication that you have an idea.

 

你认识他，对不对? - You know him, don't you? (I'm pretty sure you know him)

你认识他，对吗? - You know him, right? (same as above)

他是从中国来的，是不是? - He's from China, isn't he? (I'm almost positive he's from China)

他是从中国来的，是吗? - He's from China, right? (same as above)

 

Not a dumb question at all. It really made me think about this for awhile.

[Demonic_Duck]

I would say they are not interchangeable at the end of a sentence.

 

“是不是？” tends to be used when you're trying to pursuade the other person to agree with you, rather than asking a genuine question. It could be (as in the first video posted by arreke) that you already know full well the answer to the question, but you're asking the other person to re-confirm its truth so that you can use it as a premise for your main argument. If the answer is “不是”, the other person is arguing with you, and perhaps your next step will be to tell them that they're mistaken, or try another method to pursuade them.

 

When “是不是” is placed after the subject of a sentence (as in arreke's second video), rather than at the end, it doesn't carry this meaning; it's simply putting forward a hypothesis that you'd like the other person to confirm or deny.

 

“是吗？” is simply asking for confirmation. When you use this structure, it implies that think a positive answer is more likely than a negative one, but it's still a genuine question. You may be mildly surprised if the answer is “不是”, but your next step will probably be to ask for more information, rather than try to argue with the other person.

 

If you're genuinely neutral as to the truth or falsehood of what you're asking, you may use a simple “……吗？”, or use the “[v.]不[v.]” structure with the main verb of the sentence.

[Basil]

I agree with the satanic duck

[Qiaonansen]

Another note on 是吗. It's often used like "really" is in English. For example:

 

A: 我夏天要去中国。

B：是吗?

 

A: I'm going to China this summer.

B: Really?

 

I tend to translate this as "really" or "Is that right?", "Is that so?"

 

It carries a hint of "surprise".

 

是不是 is nothing like that.

[benkjo]

i can use those word to make sentence,For example:

 

你过吃中午饭了是吗？

have you had lunch?

 

你是不是吃过中午饭了？

have you had lunch,haven't you?

[Demonic_Duck]

Both of your sentences have a number of errors:

• Misplaced “过” in the first sentence
• Misused “过” in the second sentence: neither sentence should contain “过”, as it is normally used to show you have experienced something at least once in your life
• “中午饭” should be “午饭” or “午餐”

 

You could say “你已经吃午饭了，是吗？”, “你是不是已经吃午饭了” or “你已经吃午饭了，是不是？”. Each of these would have subtly different implications, as detailed in my earlier post (#6).

[Kamille]

At least in Taiwan people say 吃過飯. "你吃過沒?" is something I hear on a daily basis.

So I'd say "你是不是吃过午饭了" is acceptable.