是 (to be)

• Pinyin: shì
• Formation: Subject + 是 + Noun / Noun Phrase
• Hanzi breakdown: 是 = 日 (sun) + 疋 (foot/correct)

Meaning

The verb 是 (shì) connects a subject to a noun or noun phrase, similar to 'is/am/are' in English. It is used to identify, classify, or equate — but unlike English, 是 is NOT used before adjectives.

The verb 是 functions as a copula linking nouns to nouns. Its most important feature is that it ONLY connects nouns, not adjectives. In English you say 'I am happy,' but in Chinese you say 我很高兴 (without 是). Using 是 before an adjective is one of the most common beginner mistakes. The negative form is 不是, and the question form uses 吗: 你是学生吗? 是 can also express emphasis when placed before a verb phrase: 我是想帮你 ('I DO want to help you'). In equative sentences, 是 is mandatory and cannot be omitted.

Examples

1. 我是中国人。 I am Chinese.
2. 她是我们的数学老师。 She is our math teacher.
3. 这是我第一次来北京。 This is my first time coming to Beijing.

Usage Guide

Context: spoken, written, everyday

Tone: declarative

Do Say

• 他是一名医生，在市中心的医院工作。
• 今天是星期三。
• 这不是我的手机，是他的。

Don't Say

• 我是很累。(Do not use 是 before adjectives — in Chinese, adjectives function as verbs and do not need 是; say 我很累) → 我很累。
• 他是高。(是 cannot link a subject to an adjective — use 很 or other degree words instead: 他很高) → 他很高。
• 天气是好。(是 is only for noun predicates — for adjective predicates, drop 是 and use 很: 天气很好) → 天气很好。

Origin & History

In Old Chinese, 是 originally functioned as a demonstrative pronoun meaning 'this.' It gradually evolved into a copular verb during the Han Dynasty, replacing the classical construction where the subject-predicate relationship was often unmarked.

Cultural Context

Generation: All ages

Social background: Universal