...的是
Reach for this when you want to spotlight the real answer at the end of a sentence. '[CLAUSE] 的是 [ANSWER]' is the cleft-sentence form Chinese uses to say 'what actually [verbs] is [X].' The cause, effect, subject, or object you care about gets shoved to the end for emphasis. Common in writing and analytical commentary — it slows the sentence down so the punchline lands.
Structure
[VERB-CLAUSE] 的是 [HIGHLIGHTED ITEM]
...de shì...
How to Think About It
This is Chinese's version of English clefts like 'What surprised me was his answer.' The 的 nominalizes the clause before it ('让我惊讶的' = 'the thing that surprised me'), and 是 hooks the nominalized phrase to the spotlight item. Native ear hears the whole sentence as: 'the [verbing] one is [X].' Word order does the emphasis — there's no need for extra stress.
Examples
真正让挽救计划脱颖而出的，是后半段的转折。
Zhēnzhèng ràng wǎnjiù jìhuà tuōyǐng'érchū de, shì hòu bàn duàn de zhuǎnzhé.
What truly made the rescue plan stand out was the twist in the second half.
最让我感动的，是他的诚实。
Zuì ràng wǒ gǎndòng de, shì tā de chéngshí.
What moved me most was his honesty.
他最需要的，是时间。
Tā zuì xūyào de, shì shíjiān.
What he needs most is time.
Common Mistake
Learners shove the highlighted item before 的是 ('它后半段的转折是真正让计划脱颖而出的'), which collapses the cleft and the emphasis disappears. The whole point of the pattern is that the highlighted item comes AFTER 的是.
后半段的转折是真正让计划脱颖而出的。
真正让计划脱颖而出的，是后半段的转折。
Don't Confuse With
是...的
是...的 emphasizes when / where / how a past action happened ('我是昨天来的'). ...的是 emphasizes what the answer is. Different jobs entirely.
...的就是...
...的就是... adds 就 ('precisely') for extra emphasis. Use it when you want 'the answer is exactly X,' not just 'the answer is X.'
最 + ADJ + 的是...
Same cleft, with 最 + adjective in front to highlight superlatives ('最让人吃惊的是他的回答'). Same machinery, just adds a superlative.
Practice
最让我感动 ___ 是他的诚实。
Show answer
的
他最需要的 ___ 时间。
Show answer
是
Arrange: 是 / 我 / 的 / 中文 / 最喜欢
Show answer
我最喜欢的是中文。
What surprised me was his answer.
Show answer
让我惊讶的，是他的回答。
Highlight what matters most about something using ...的是...
Show answer
这本书最有意思的，是结尾。
Hear It in Real Episodes
This pattern appears in 1 Fluentide episode: