X 既是 ... 也是 ...
Reach for this when one subject holds two identities or roles at the same time — 'X is both A and B.' Used for nouns and roles, not adjectives. More formal and structured than 又...又..., and reads as deliberate rather than offhand. Common in introductions ('she is both a writer and a doctor'), official descriptions, news profiles, and reflective writing. Pick this when you want each role to feel weighty and properly named, not just casually stacked together.
Structure
X + 既是 + Noun/Role₁, 也是 + Noun/Role₂
jì shì... yě shì...
How to Think About It
既是...也是... names two equal identities and binds them together. Think of it as Chinese's clean way to say 'A is X, and A is also Y' without repeating the subject. 既 sets up 'on one hand,' 也 closes with 'on the other.' Reserve it for nouns and roles. For adjectives ('tall and handsome'), use 又...又.... For comparable formality with adjectives, use 既...又....
Examples
她既是我的同事，也是我的好朋友。
Tā jì shì wǒ de tóngshì, yě shì wǒ de hǎo péngyou.
She's both my colleague and my close friend.
北京既是中国的首都，也是一个历史名城。
Běijīng jì shì Zhōngguó de shǒudū, yě shì yīgè lìshǐ míngchéng.
Beijing is both China's capital and a famous historical city.
这次旅行既是一次休息，也是一次学习。
Zhè cì lǚxíng jì shì yī cì xiūxi, yě shì yī cì xuéxí.
This trip is both a rest and a learning experience.
他既是父亲，也是孩子最好的老师。
Tā jì shì fùqīn, yě shì háizi zuì hǎo de lǎoshī.
He's both a father and his child's best teacher.
Common Mistake
Learners drop 也是 and just write 既是, treating 既 like a standalone 'both.' 既 only works as the first half of a paired structure. Without 也是 (or 又) closing the pair, the sentence sounds unfinished.
他既是医生，作家。
他既是医生，也是作家。
Don't Confuse With
又...又...
Stacks adjectives or verbs ('cheap and tasty'). 既是...也是... names two nouns or roles. Don't mix — 又是医生又是作家 sounds wrong; you want 既是医生也是作家.
既...又...
Same pairing logic but works with adjectives or verbs, not noun identities. Use 既...又... for 'both convenient and cheap'; use 既是...也是... for 'both a teacher and a parent.'
不仅是...还是...
'Not only X but also Y' — adds emphasis that Y goes beyond X. 既是...也是... treats the two as equal. 不仅是...还是... ranks Y as more or additional.
Practice
Fill in: 上海 ___ 一个大城市， ___ 一个国际港口。
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既是...也是
Translate to Chinese: Reading is both a hobby and a way to learn.
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读书既是一种爱好，也是一种学习的方式。
Arrange: 既是 / 也是 / 朋友 / 我的 / 老师 / 我的 / 他
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他既是我的老师，也是我的朋友。
Use 既是...也是... to describe someone you know who has two roles.
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我妈妈既是一名医生，也是一名作家。
Hear It in Real Episodes
This pattern appears in 1 Fluentide episode:
Related Grammar Patterns
Acquire by listening
Hear X 既是 ... 也是 ... in real Chinese, not in a textbook.
Fluentide picks the next news episode at your level, so this pattern shows up again and again in real context. The transcript marks it, the audio drills it. Free to start, no card.