「是」字句 "shì" zì jù
「是」字句（"shì" zì jù）means “A 是 B: 'A is B' (linking two nouns)”. 是 links two nouns/noun phrases (A is B). Formation: A + 是 + B（A 就是 B）
A 是 B: 'A is B' (linking two nouns)
HSK1Formation
A + 是 + B（A 就是 B）
Explanation
是 links two nouns/noun phrases (A is B). Use it only between nouns — NOT before an adjective (that takes 很, see 很+adjective). Negate with 不是.
Examples
我 是 学生。
wǒ shì xuésheng.
I am a student.
这 是 我的手机。
zhè shì wǒ de shǒujī.
This is my phone.
Note
Negative = 不是: 我不是老师.
FAQ
「是」字句 — what does it mean and how is it used?
A 是 B: 'A is B' (linking two nouns). 是 links two nouns/noun phrases (A is B). Use it only between nouns — NOT before an adjective (that takes 很, see 很+adjective). Negate with 不是.
「是」字句 — how do you form it?
A + 是 + B（A 就是 B）
「是」字句 — any usage notes?
Negative = 不是: 我不是老师.