1 · The basic sentence
A is B with shì
the linking verb between two nouns
Shì links two nouns — “A is B” — but never a noun and an adjective.
是 joins two nouns: 我是老师, “I am a teacher”. There is no word for “a” or “the”, so the noun follows directly: 她是英国人, “she is British”. And 是 has one form for every person and every time: “am”, “is”, “are”, “was” and “were” are all 是.
The negative is 不是, always with bú, because 是 has the fourth tone: 他不是医生, “he is not a doctor”. It is never negated with 没, not even about the past. A question adds 吗: 你是学生吗？
English “is” does two jobs that Chinese keeps apart. “He is a teacher” links two nouns and takes 是; “he is tall” links a noun to an adjective and does not: 他很高. Chinese adjectives work like verbs — “to be tall” — so they need no “is”. Putting 是 in front of one is one of the most common mistakes of English-speaking beginners.
是 also identifies things — 这是我的书, “this is my book” — and introduces people: 我是王明. What it does not do is help another verb. “I am going” is 我去, not wǒ shì qù: the English “am” in “am going” has no counterpart here.
The form
| A is B | 我是学生。 |
| A is not B | 我不是学生。 |
| question with ma | 你是学生吗？ |
| this is … | 这是我的书。 |
| no shì before an adjective | 他很高。 |
The rules one by one
The form this topic is about
Shì joins two nouns: A shì B, with no word for “a” or “the”.
我妈妈是医生。My mother is a doctor.
The negative is bú shì; the bù is always said bú here, because shì has the fourth tone.
她不是中国人。She is not Chinese.
Shì does not link a noun and an adjective; hěn stands there instead.
这本书很贵。This book is expensive.
Shì does not go in front of an ordinary verb.
我喜欢猫。I like cats.
A closer look
When shì can be left out
In positive sentences about dates, ages, prices and where somebody comes from, everyday speech often drops 是: 今天星期五, 我二十岁, 这个十块. The noun phrase itself works as the predicate. In the negative it must come back: 今天不是星期五.
When 是 does stand before an adjective or a verb, it is stressed and means “really” or “it is true that”: 他是很聪明, “he really is clever”. That emphatic use is a later topic; at the start, keep 是 for two nouns.
Exceptions and special cases (1)
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a positive sentence gives a date, an age or a price
是 can be left out.
我女儿今年五岁。My daughter is five this year.
A number phrase can work as the predicate on its own, so the link is not needed; the negative still needs 不是.
How to spot it
- 是
- 不是
Example sentences
我是美国人。I'm American.
这是我的朋友李华。This is my friend Li Hua.
那不是我的手机。That isn't my phone.
你是王老师吗？Are you Teacher Wang?
今天是星期五。Today is Friday.
我哥哥是大学生，我是中学生。My older brother is a university student and I am at secondary school.
7 more example sentences
我爸爸是工程师。My father is an engineer.
这不是茶，是咖啡。This isn't tea, it's coffee.
他们是我的同学。They are my classmates.
明天是我的生日。Tomorrow is my birthday.
那个人是谁？Who is that person?
北京是中国的首都。Beijing is the capital of China.
你的老师是中国人吗？Is your teacher Chinese?
Worth knowing (1)
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Shì as “yes”
Asked a question with 是 in it, you can answer “yes” with 是 or 是的, and “no” with 不是. This works only because the question itself contained 是.
是的，我是张老师。Yes, I'm Teacher Zhang.
The trap English speakers fall into
Watch out
English needs “is” in “he is tall”, so it feels natural to reach for 是. But a Chinese adjective already contains the “is”: 高 means “to be tall”. What goes between the subject and the adjective is usually 很, said lightly.
Shì links nouns: use it for “is a teacher”, never for “is tall”.
Your turn
9 exercises on this topic. Your answers are checked in the browser; none of them leaves your device.