是……的 structure
Reach for this when the listener already knows that an action happened, and you want to highlight a specific detail about it — the WHEN, WHERE, HOW, or WHO. 是 sits before the highlighted detail; 的 closes the sentence. Used for past actions only, and only when the action itself isn't in question. Everyday and constant in speech: '我是昨天来的' isn't 'I came yesterday' (new info) — it's 'it was yesterday that I came' (the coming is known; the timing is what you're pointing at).
Structure
Subject + 是 + [Time/Place/Manner/Agent] + V + (Object) + 的
shì... de
How to Think About It
是...的 is Chinese's spotlight. Drop it on the part of the sentence you want to highlight — the WHEN, WHERE, or HOW of a past action that's already on the table. English does this with intonation or cleft sentences ('it was yesterday that I came'); Chinese needs the 是...的 frame around the highlighted detail. Without it, you're just reporting that the action happened. With it, you're saying 'here's the detail you wanted.'
Examples
我是昨天来北京的。
Wǒ shì zuótiān lái Běijīng de.
It was yesterday that I came to Beijing.
这本书是在图书馆借的。
Zhè běn shū shì zài túshūguǎn jiè de.
This book was borrowed from the library.
他是坐高铁去上海的。
Tā shì zuò gāotiě qù Shànghǎi de.
He went to Shanghai by high-speed rail.
这件衣服是我妈妈买的。
Zhè jiàn yīfu shì wǒ māma mǎi de.
This piece of clothing was bought by my mom.
Common Mistake
Learners use 是...的 for events that haven't been established yet, treating it like a regular past tense. 是...的 only works when the action itself is known — you're filling in a missing detail. For first-time mentions of past actions, just use 了 instead. '我昨天来了' announces the event; '我是昨天来的' answers 'when did you come?'
我是昨天吃饭了。
我是昨天来的。
Don't Confuse With
了 (perfective)
了 marks that an action completed — used for new information. 是...的 highlights a specific detail about a known completed action. Don't combine them: 我是昨天来的 is correct; 我是昨天来了的 is not.
的 (possession/modifier)
Stand-alone 的 marks possession (我的书) or attributes (红色的). The 是...的 structure uses 的 as a sentence-final marker, paired with 是.
在...V
'In the process of V-ing' — present continuous. 是...的 is exclusively for highlighting details of a past action that's already known.
Practice
Fill in: 我 ___ 上个星期 ___ 这里 ___ 。
Show answer
是...来...的
Translate to Chinese: I came here by bus. (highlighting how)
Show answer
我是坐公共汽车来的。
Arrange: 是 / 的 / 在 / 学 / 中文 / 中国 / 他
Show answer
他是在中国学中文的。
Use 是...的 to highlight when or where you did something in the past.
Show answer
我是去年开始学中文的。
Hear It in Real Episodes
This pattern appears in 1 Fluentide episode:
Related Grammar Patterns
Acquire by listening
Hear 是……的 structure in real Chinese, not in a textbook.
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