是
Pattern
A 是 B
Key words
Core idea
是 links one noun-like idea to another. It identifies people, labels objects, gives roles, names days, and places something into a category.
The trap is English “is.” English uses “is” for identity and adjectives, but Mandarin does not use 是 before ordinary adjective predicates.
What to check before using it
Before using 是, check what follows it. If the next part is a noun, role, name, date, or category, 是 is probably right.
If the next part is an adjective-like state verb, the sentence probably does not need 是. Mandarin usually lets state verbs predicate directly, often with an adverb such as 很.
For questions, 是 works naturally with both A-not-A and 吗 patterns. The later 是不是 pattern is built from this same verb, but it asks for confirmation rather than simply linking two noun-like ideas.
Examples
她是老师。
Tā shì lǎoshī.
She is a teacher.
是 links the person to a noun category.
今天是星期三。
Jīntiān shì xīngqīsān.
Today is Wednesday.
这是我的票。
Zhè shì wǒ de piào.
This is my ticket.
Common mistakes
Avoid
她是很忙。
Use
她很忙。
Do not use 是 before ordinary adjective predicates like 忙, 好, or 贵.
Avoid
我是去学校。
Use
我去学校。
Use 是 for identifying nouns, not before a normal action verb.
Seen in stories
The Name on the Cup
阿哲拿起杯子，问：“这是我的吗？”
Azhe picks up the cup and asks, “Is this mine?”
The Name on the Cup
小晴说：“不是，这是我的。”
Xiaoqing says, “No, this is mine.”
The New Classmate
小语看橘猫，说：“喜欢，它也是同学吗？”
Xiaoyu looks at the orange cat and says, “I do. Is it a classmate too?”
The Umbrella at the Door
小美笑了：“小伞也是伞吧。”
Xiaomei laughs: “A small umbrella is still an umbrella, right?”
The Weather on the Phone
手机说今天是晴天。
The phone says today is sunny.
Show 7 more story examples
The Weather on the Phone
小美问：“真的是晴天吗？”
Xiaomei asks, “Is it really sunny?”
Two Cups of Soy Milk
阿哲问：“冰的是我的吗？”
Azhe asks, “Is the iced one mine?”
Two Cups of Soy Milk
阿哲笑了：“我说天气热，不是豆浆热。”
Azhe laughs: “I meant the weather was hot, not the soy milk.”
The Cat at the School Gate
下雨的时候，骑楼就是它的家。
When it rains, the covered walkway becomes its home.
The Cat at the School Gate
小晴说：“它是我们的气象员。”
Xiaoqing says, “It is our weather reporter.”
The Cat at the School Gate
午后下起大雨，他们才发现树下是警卫刚放好的暖坐垫。
When heavy rain begins that afternoon, they discover the guard had just put a warm cushion under the tree.
Saturday School
那个人说：“今天不是星期五，今天是星期六。”
That person says, "Today is not Friday, today is Saturday."