之所以……(是因为/在于)……
Reach for this when you want to lead with the result and then drop the cause as a kind of reveal — 'the reason X happened is because/lies in Y.' It flips normal 因为...所以... order, so the listener already knows the outcome and is waiting for the explanation. Common in opinion pieces, business analysis, and news commentary: 'The reason Sam's Club gained a foothold in China is that it cracked the local code.'
Structure
[SUBJECT] 之所以 [RESULT]，是因为/在于 [REASON]
...zhī suǒ yǐ..., shì yīn wèi / zài yú...
How to Think About It
Think of 之所以 as a spotlight on the outcome — you put the consequence first because it's already what everyone's looking at. The reason then lands with extra weight. 在于 is more pointed than 是因为: it says the cause 'lies in' one specific thing, not a fuzzy bundle of factors. Reordering to put cause first kills the rhetorical punch and turns it into a flat 因为 sentence.
Examples
他之所以成功，是因为他从不放弃。
Tā zhī suǒ yǐ chénggōng, shì yīnwèi tā cóng bù fàngqì.
The reason he succeeded is that he never gave up.
我之所以选择这份工作，在于它的发展空间。
Wǒ zhī suǒ yǐ xuǎnzé zhè fèn gōngzuò, zàiyú tā de fāzhǎn kōngjiān.
The reason I chose this job lies in its growth potential.
中国之所以发展这么快，是因为改革开放。
Zhōngguó zhī suǒ yǐ fāzhǎn zhème kuài, shì yīnwèi gǎigé kāifàng.
The reason China developed so fast is the reform and opening up.
Common Mistake
Learners often try to use 之所以 with the cause clause, mirroring 因为. But 之所以 attaches to the RESULT — the thing being explained. Putting the reason after 之所以 produces a sentence natives can't parse.
他之所以下雨了，所以没来。
他之所以没来，是因为下雨了。
Don't Confuse With
因为……所以……
Neutral cause-then-result order. Pick 因为...所以... in conversation and basic writing. Pick 之所以...是因为... when you want to highlight the result first for emphasis.
由于……因此……
Formal cause-then-result, common in news and reports. Same direction as 因为...所以..., not the flipped version.
原因在于……
Stands alone as 'the reason lies in...'. Use it when the result was just stated in a previous sentence; use 之所以...在于... when you want both halves in one sentence.
Practice
他____以迟到，是因为路上堵车。
Show answer
之所
我之所以喜欢这个城市，____在于它的文化。
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在于
Put in order: [是因为 / 学得 / 之所以 / 她 / 她 / 每天练习 / 好]
Show answer
她之所以学得好，是因为她每天练习。
Translate to Chinese: 'The reason I am learning Chinese is that I want to work in Shanghai.'
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我之所以学中文，是因为我想在上海工作。
Write one sentence explaining why a company or person you admire succeeded, using 之所以……是因为……
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Example answer: 这家公司之所以成功，是因为它真正了解用户的需求。 (The reason this company succeeded is that it truly understands user needs.)
Hear It in Real Episodes
This pattern appears in 1 Fluentide episode: