之所以...係因為...

The Reason Is Because

Level 5Sounds Like zi1 so2 ji5 . . . hai6 jan1 wai6 . . .

Subject + 之所以 (zi1 so2 ji5) + [Result], 係因為 (hai6 jan1 wai6) + [Cause].

How It Works

The pattern 之所以...係因為... (zi1 so2 ji5... hai6 jan1 wai6...) is a formal rhetorical device used to provide an analytical explanation for a situation.

1. Structure and Word Order
Unlike the English 'The reason why...', the subject in Cantonese usually comes before the phrase 之所以.
Example: 佢 (Subject) + 之所以 (The reason why) + 成功 (Result) + 係因為 (is because) + 佢好勤力 (Cause).

2. Grammatical Components

  • 之 (zi1): A formal particle from Classical Chinese that helps nominalize the clause.
  • 所以 (so2 ji5): Literally 'the reason' or 'that which causes'.
  • 係 (hai6): The copula 'to be' is essential here to link the result to the cause.
  • 因為 (jan1 wai6): Introduces the reason.

3. Register and Usage
This is a Level 5 (Advanced) pattern because it belongs to written-style Cantonese (書面語). You will hear it in news reports, formal speeches, or academic contexts. In casual daily life, speakers prefer the simpler 因為...所以... or just saying the result followed by 係因為.

Examples (4)

  1. 佢之所以成功，係因為佢好勤力。

    The reason he succeeded is because he is very hardworking.

    Word by Word: He [reason why] succeed, is because he very hardworking.

    Note how the subject '佢' (keoi5) precedes '之所以'.

  2. 我之所以揀呢間公司，係因為福利好。

    The reason I chose this company is because the benefits are good.

    Word by Word: I [reason why] choose this [classifier] company, is because benefits good.

    This structure highlights the 'benefits' as the primary motivation for the choice.

  3. 廣東話之所以難學，係因為有九個聲調。

    The reason Cantonese is hard to learn is because it has nine tones.

    Word by Word: Cantonese [reason why] hard learn, is because have nine [classifier] tones.

    A formal way to state a well-known fact about the language.

  4. 呢度之所以咁多人，係因為今日有折。

    The reason there are so many people here is because there is a sale today.

    Word by Word: Here [reason why] so many people, is because today have discount.

    Even in slightly more common scenarios, using this pattern adds an explanatory, analytical tone.

Common Mistakes

  • Putting the subject after 之所以.

    Different Meaning之所以佢成功，係因為佢好勤力。
    佢之所以成功，係因為佢好勤力。

    之所以佢成功 is possible in writing, but the usual order puts the subject before the marker, as in 佢之所以成功.

  • Using the pattern in casual, low-register conversation.

    Different Meaning我之所以想食飯，係因為我肚餓。
    我肚餓，所以想食飯。

    While grammatically correct, using this formal structure for simple things like being hungry sounds unnaturally stiff. Use the standard 'Because... so...' instead.

How It Connects

Tap a pattern to see what it builds on and what it leads to.

之所以...係因為...Level 5The Reason Is Because

Learn This First

The pattern '之所以...係因為...' is a formal frame used to state an outcome before explaining its cause. To understand it, learners need to be familiar with the basic causal conjunctions '因為' (because) and '所以' (so), as well as the use of '係' to link clauses. It essentially functions as a more sophisticated version of the 'The reason why... is because...' structure.

Words in This Pattern

因为