Introduction
因为 (yīnwèi) gives the reason, 所以 (suǒyǐ) gives the result — and Chinese is happy to use both at once, where English insists on one or the other. 因为下雨，所以我没去。(Yīnwèi xià yǔ, suǒyǐ wǒ méi qù.) — literally "because it rained, therefore I didn't go", and that is correct Chinese.
Overview
Structure: 因为 (yīnwèi) + Reason，所以 (suǒyǐ) + Result
| Pattern | Example | Translation |
|---|---|---|
| 因为……，所以…… | 因为下雨，所以我没去。(Yīnwèi xià yǔ, suǒyǐ wǒ méi qù.) | It rained, so I didn't go. |
| Result，因为 + Reason | 我没去，因为下雨。(Wǒ méi qù, yīnwèi xià yǔ.) | I didn't go, because it rained. |
| 因为……（no 所以） | 因为很忙，我没去。(Yīnwèi hěn máng, wǒ méi qù.) | I was busy, so I didn't go. |
| 所以……（no 因为） | 下雨了，所以我没去。(Xià yǔ le, suǒyǐ wǒ méi qù.) | It rained, so I didn't go. |
| 为什么……？因为…… | 你为什么没去？因为下雨。(Nǐ wèishénme méi qù? Yīnwèi xià yǔ.) | Why didn't you go? Because it rained. |
Using both halves is right, not redundant:
- ✓ 因为下雨，所以我没去。(Yīnwèi xià yǔ, suǒyǐ wǒ méi qù.)
- English has to drop one — "Because it rained, so I didn't go" is wrong in English and perfectly normal in Chinese.
- You may drop either one, but never swap their order: 因为 (yīnwèi) always sits with the reason, 所以 (suǒyǐ) always with the result.
- The reason can also come second: 我没去，因为下雨。(Wǒ méi qù, yīnwèi xià yǔ.) — then 所以 disappears.
Examples
因为下雨，所以我没去。
Yīnwèi xià yǔ, suǒyǐ wǒ méi qù.
It rained, so I didn't go.
我没去，因为我很忙。
Wǒ méi qù, yīnwèi wǒ hěn máng.
I didn't go, because I was busy.
因为他不舒服，所以今天没来上班。
Yīnwèi tā bù shūfu, suǒyǐ jīntiān méi lái shàngbān.
He wasn't well, so he didn't come in today.
你为什么学中文？因为我喜欢中国文化。
Nǐ wèishénme xué Zhōngwén? Yīnwèi wǒ xǐhuan Zhōngguó wénhuà.
Why are you learning Chinese? Because I like Chinese culture.
这儿太贵了，所以我们去别的地方吧。
Zhèr tài guì le, suǒyǐ wǒmen qù bié de dìfang ba.
It's too expensive here, so let's go somewhere else.
因为快要考试了，所以我每天都学习。
Yīnwèi kuài yào kǎoshì le, suǒyǐ wǒ měi tiān dōu xuéxí.
The exam's coming up, so I study every day.
Usage Notes
- 因为 (yīnwèi) is the standard answer to 为什么 (wèishénme). In a reply it stands alone: 因为下雨。(Yīnwèi xià yǔ.)
- 所以 (suǒyǐ) opens the result clause and cannot start a sentence on its own without a reason before it.
- 为 (wèi) in 因为 is 4th tone — yīnwèi, the same 为 as in 为什么 (wèishénme).
- 虽然……但是…… (suīrán … dànshì …) works the same way — both halves kept — but for contrast rather than cause.
- In speech the reason clause often drops 因为 (yīnwèi) entirely and keeps only 所以 (suǒyǐ): 下雨了，所以我没去。(Xià yǔ le, suǒyǐ wǒ méi qù.)