是否 (whether or not)

• Pinyin: shìfǒu
• Formation: 是否 + Verb / Adjective
• Hanzi breakdown: 是 = 日 (sun) + 疋 (correct), meaning to be/yes; 否 = 不 (not) + 口 (mouth), meaning no/not

Meaning

是否 (shìfǒu) means 'whether or not' or 'is or is not.' It introduces an embedded yes-no question, typically in formal or written contexts, asking whether something is the case.

是否 is the formal equivalent of the colloquial 是不是. It is used to embed a question within a larger statement, often after verbs like 确认 (confirm), 了解 (understand), 考虑 (consider), or 决定 (decide). Unlike 是不是 which can appear as a tag question at the end of a sentence, 是否 always appears before the verb or adjective being questioned. It is standard in official documents, surveys, academic writing, and formal correspondence. 是否 can be followed by a verb, adjective, or verb phrase. It does not require a question mark when embedded in a declarative sentence.

Examples

1. 请确认您是否已经收到我们的邮件。 Please confirm whether you have received our email.
2. 我不确定他是否同意这个方案。 I'm not sure whether he agrees with this plan.
3. 公司正在评估是否有必要扩大生产规模。 The company is evaluating whether it is necessary to expand production scale.

Usage Guide

Context: written, formal speech, official documents

Tone: inquiring

Do Say

• 请问您是否需要开发票？
• 我们需要讨论是否继续推进这个项目。
• 调查问卷询问居民是否满意社区服务。

Don't Say

• 你是否喜不喜欢吃辣？(是否 already contains the positive-negative contrast — adding 喜不喜欢 is redundant) → 你是否喜欢吃辣？
• 是否他来了吗？(是否 embeds a question and should not be combined with the question particle 吗) → 他是否来了？

Origin & History

是否 is a classical construction combining 是 (yes/is) and 否 (no/not). In Classical Chinese, the 是否 pattern was already used to pose alternatives. It remains one of the most recognizable formal registers in modern Mandarin.

Cultural Context

Generation: All ages

Social background: Universal