X 是 ... 的
Reach for 是...的 when an action already happened and you want to spotlight a specific detail about HOW, WHEN, WHERE, or WITH WHOM it happened — not whether it happened. The fact of the event is shared ground; you are zooming in on one piece of it. It's the structure behind sentences like 'I came BY TRAIN,' 'She arrived LAST WEEK,' 'He told me AT THE OFFICE.' Common in question-and-answer turns about past events.
Structure
[SUBJECT] 是 [TIME / PLACE / MANNER / AGENT] [VERB] 的
shì... de
How to Think About It
是...的 is a spotlight on the prepositional detail of a past event, not a tense marker. The verb is past — but you do NOT use 了 here, because 是...的 already signals completion and the spotlight is on the modifier, not on the action's completion. If your sentence is about WHETHER something happened, use 了. If it's about HOW/WHEN/WHERE it happened, use 是...的.
Examples
我是坐高铁来的。
Wǒ shì zuò gāotiě lái de.
I came by high-speed train.
她是去年回国的。
Tā shì qùnián huí guó de.
She returned to her home country last year.
这件事是他告诉我的。
Zhè jiàn shì shì tā gàosu wǒ de.
It was he who told me about this.
Common Mistake
Learners pile 了 onto a 是...的 sentence because they think every past event needs 了. In 是...的 structure, the 的 absorbs the past-ness — adding 了 sounds wrong to natives.
我是昨天来了的。
我是昨天来的。
Don't Confuse With
了 (past action)
Use 了 when the listener doesn't know the event happened. Use 是...的 when they already know it happened and you're answering a question about the manner/time/place/agent.
X 是 + Noun
Simple identification — '他是医生.' That 是 is the main verb. In 是...的, the 是 is highlighting one element of a past sentence and the real verb sits between 是 and 的.
...的 (modifier)
Plain 的 makes a noun-modifier ('我的书'). The 的 in 是...的 sits at the end of a clause and works together with 是 — different job entirely.
Practice
你 ___ 怎么来的？我是开车来的。
Show answer
是
他是在北京出生 ___。
Show answer
的
Put in order: [是 / 我 / 的 / 二零二零年 / 在 / 上海 / 认识 / 他]
Show answer
我是二零二零年在上海认识他的。
Translate to Chinese (highlight the means): 'I came by plane.'
Show answer
我是坐飞机来的。
Someone knows you moved here. They ask 你是什么时候来的? Answer in one 是...的 sentence.
Show answer
Example answer: 我是去年八月来的。 (I came last August.)
Hear It in Real Episodes
This pattern appears in 2 Fluentide episodes: