因为... (所以)...
Reach for this when you want to explicitly link a cause to a result — 'because X, so Y.' It's the workhorse cause-and-effect connector in Chinese. 因为 names the reason; 所以 introduces the consequence. In careful writing both halves appear; in casual speech, 所以 can be dropped, and sometimes 因为 itself disappears in answers to '为什么?' ('Why?' → '因为太贵了。'). HSK 1 essential and used constantly in everyday conversation.
Structure
因为 [REASON], 所以 [RESULT]
yīnwèi... suǒyǐ...
How to Think About It
Chinese typically keeps BOTH halves. Where English picks 'because' OR 'so,' Chinese says both — they reinforce each other instead of duplicating. In writing the pair is the safe default; in speech you can drop one, but never use 所以 by itself at the start of a sentence as a sentence connector the way English does.
Examples
因为今天下雨，所以我没去公园。
Yīnwèi jīntiān xià yǔ, suǒyǐ wǒ méi qù gōngyuán.
Because it rained today, I didn't go to the park.
因为他生病了，所以没来上班。
Yīnwèi tā shēngbìng le, suǒyǐ méi lái shàngbān.
Because he got sick, he didn't come to work.
因为这家餐厅很有名，所以人很多。
Yīnwèi zhè jiā cāntīng hěn yǒumíng, suǒyǐ rén hěn duō.
Because this restaurant is famous, there are a lot of people.
Common Mistake
Learners copy English and use only 因为 or only 所以, leaving the other half implied. Both halves coexist in Chinese: dropping 所以 in speech is fine, but adding both is never wrong, while combining 因为 with 但是 instead of 所以 sounds confused.
因为下雨了，但是我没出门。
因为下雨了，所以我没出门。
Don't Confuse With
由于……因此……
Same meaning, much more formal. Use 因为……所以…… in conversation; use 由于……因此…… in essays, news, and reports.
既然……就……
既然 introduces a premise already known to both speakers ('given that'). 因为 introduces a reason as new information explaining a result.
之所以……是因为……
Reversed cause-effect order ('the reason… is because…'). Used when you want to flag the result first and then explain its cause.
Practice
Fill in the blank: ____ 我累了，所以我去睡觉了。
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因为
Fill in the blank: 因为天气不好， ____ 我们不出门。
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所以
Arrange into a sentence: 因为 / 所以 / 我 / 学习 / 在 / 喜欢 / 中文 / 北京
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因为我喜欢中文，所以我在北京学习。
Translate to Chinese: Because I'm hungry, I want to eat something.
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因为我饿了，所以我想吃点东西。
Use 因为……所以…… to explain one decision you made today.
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因为今天很冷，所以我穿了厚外套。
Hear It in Real Episodes
This pattern appears in 1 Fluentide episode:
Related Grammar Patterns
Acquire by listening
Hear 因为... (所以)... in real Chinese, not in a textbook.
Fluentide picks the next news episode at your level, so this pattern shows up again and again in real context. The transcript marks it, the audio drills it. Free to start, no card.