As an adverb, 就 (jiù) can be placed before the predicate to add emphasis. It often has an intense or provocative feel to it, similar to "just," like how we sometimes say in English "it's just not right!" This emphasis very often appears as 就是.
就是 Used as "is exactly"
Structure
就 frequently comes before the verb 是, and "就是" means "(is) exactly".
Examples
- 那个 人 就 是 她 的 新 男朋友。Nàge rén jiù shì tā de xīn nánpéngyou.That guy is her new boyfriend.
- 他 就 是 你 要 找 的 人 。Tā jiù shì nǐ yào zhǎo de rén.He's just the person that you're looking for.
- 我们 就 是 他 的 家人 。Wǒmen jiù shì tā de jiārén.We're his family.
- 你 就 是 个 笨蛋！Nǐ jiù shì gè bèndàn!A moron is precisely what you are!
- 他 就 是 那 个 骗子！Tā jiù shì nàge piànzi!That conman is him!
就是 as "Only Because"
就是 can be used to intensify the predicate to mean "only (because of) that and nothing else." In this case, 是 can't be omitted. In many cases, you could also add in an 因为, but it's not required.
Examples
- 他 不 去 旅游 就是 不 想 花钱 。 Tā bù qù lǚyóu jiùshì bù xiǎng huāqián. He didn't travel only because he doesn't want to spend the money.
- 你 不 参加 比赛 就是 怕 输 吗 ？ Nǐ bù cānjiā bǐsài jiùshì pà shū ma? You're not entering the competition just because you're afraid of failure?
- 他 这样 说 就是 嫉妒 我 。 Tā zhèyàng shuō jiùshì jídù wǒ. He said this only because he envies me.
- 她 问 这么 多，就是 担心 你 。 She asked so many questions only because she's worried about you.
- 她 就是 漂亮 ，没 别的 优势 。 Tā jiùshì piàoliang, méi biéde yōushì.She's just pretty; she doesn't have any other strengths.
就 Used with Other Verbs
In the examples above, 就 pairs exclusively with the verb 是. But 就 can also come before other verbs, with similar emphatic effect. In these cases, it's also OK to use 就是 before the other verbs as well.
Structure
就（是）+ Verb
就（是）+ 不 + Verb
Examples
- 我 就 要 去！Wǒ jiù yào qù! I just want to go!
- 我 就是 喜欢 他。Wǒ jiù shì xǐhuan tā.I just like him.
- 我 就 不 告诉 你 。Wǒ jiù bù gàosu nǐ.I'm just not going to tell you.
- 我 父母 就是 不 让 我 一个人 去 。 Wǒ fùmǔ jiùshì bù ràng wǒ yīgèrén qù.My parents simply won't let me go alone.
- 这个 学生 就是不 听 老师 的 话 。Zhège xuéshēng jiù bù tīng lǎoshī de huà.The student just wouldn't listen to his teacher.
As you may have noticed, many of these uses of 就 or 就是 carry a flippant, stubborn tone, referred to as 任性 (rènxìng) in Chinese.
See also
Sources and further reading
Books
Dictionaries
Category:B1 grammar points