2 · Linking clauses
Because and so: yīnwèi … suǒyǐ
cause and result
The reason comes first with yīnwèi and the result second with suǒyǐ — and Chinese is happy to use both words at once.
To give a reason, Chinese puts 因为 before the cause and 所以 before the result: 因为下雨，所以我没去, “because it rained, I didn’t go”. English uses one word, “because” or “so”, and using both in one sentence counts as a mistake. In Chinese the pair is normal, and in careful speech and writing it is common: one word opens the reason, the other announces that the result is coming.
The usual order is cause first, result second — the order in which things happen, which Chinese prefers in general. English often turns this round: “I didn’t go because it rained”. Chinese can do that too, but then the reason sounds like an afterthought: 我没去，因为下雨了. In that order 所以 disappears, because there is no result left for it to introduce.
Either word may be dropped, and in relaxed speech one is often enough: 我太累了，所以想早一点儿睡. What does not change is the position. 所以 always opens its clause, in front of the subject. 因为 can stand before or after the subject: 他因为生病没来 is as good as 因为他生病了，所以没来.
English “so” does two jobs, and 所以 does only one of them. “So” meaning “therefore” is 所以; “so” meaning “to such a degree” is 这么, 那么 or 太. “I am so tired” is 我太累了, never a sentence with 所以. The question that asks for a reason is 为什么, and the answer starts with 因为.
The form
| cause, then result | 因为下雨，所以我没去。 |
| only 因为 | 因为下雨，我没去。 |
| only 所以 | 下雨了，所以我没去。 |
| the reason added afterwards | 我没去，因为下雨了。 |
| 因为 after the subject | 我因为下雨没去。 |
| asking why | 你为什么没去？ |
The rules one by one
The form this topic is aboutThe word that calls for it
The reason comes first with 因为 and the result second with 所以; the two words may stand in the same sentence.
因为路上堵车，所以他迟到了。He was late because of the traffic on the way.
所以 opens its clause, in front of the subject; 因为 can stand before or after the subject.
她因为感冒了，今天没来上班。She has a cold, so she didn’t come to work today.
When the reason follows the result, it takes 因为 alone and 所以 is dropped.
我今天不喝咖啡，因为晚上想早一点儿睡。I’m not having coffee today because I want to go to bed early tonight.
A question with 为什么 is answered with 因为.
你为什么不去？——因为我太忙了。Why aren’t you going? — Because I’m too busy.
A closer look
Why Chinese marks both halves
Many of the linking patterns in this area come in pairs: 虽然 … 但是, 如果 … 就, 因为 … 所以. Chinese has no verb endings and no subordinate word order to show which clause depends on which, so the relation is signalled at both ends. The second word works like a signpost: when 所以 arrives, the listener knows that everything before it was the reason.
In writing, 因此 often replaces 所以, and 由于 replaces 因为 at the start of a sentence. They mean the same thing in a more formal register; the everyday pair is the one to use in conversation.
Exceptions and special cases (1)
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the result is stated first on purpose, in order to explain it
the result clause takes 之所以 and the reason follows with 是因为.
我之所以学中文，是因为喜欢中国电影。The reason I am learning Chinese is that I like Chinese films.
This is the one place where the word for “so” appears in the first half. It is a formal pattern for explanations: “the reason why X is that Y”.
How to spot it
- 因为
- 所以
- 为什么
- 因为…所以…
Example sentences
因为今天很冷，所以我多穿了一件衣服。Because it is cold today, I have put on an extra layer.
他昨天晚上没睡好，所以今天很累。He didn’t sleep well last night, so he is tired today.
因为这家饭馆的菜很好吃，我们常常来这儿吃饭。We often eat here because the food in this restaurant is good.
我没买那双鞋，因为太贵了。I didn’t buy that pair of shoes because they were too expensive.
你为什么没给我打电话？——因为我的手机没电了。Why didn’t you call me? — Because my phone’s battery was dead.
她因为工作太忙，很少回家。Her work keeps her so busy that she rarely goes home.
7 more example sentences
因为明天有考试，他今天晚上不出去了。He has an exam tomorrow, so he isn’t going out tonight.
我第一次来这儿，所以不太认识路。It’s my first time here, so I don’t really know the way.
因为他说得太快，所以我没听懂。He spoke too fast, so I didn’t understand.
商店已经关门了，所以我们明天再来吧。The shop has already closed, so let’s come back tomorrow.
孩子们很高兴，因为今天不用上学。The children are happy because they don’t have to go to school today.
因为路太远，我们坐出租车去吧。It’s too far, so let’s take a taxi.
你为什么这么高兴？——因为我找到工作了！Why are you so happy? — Because I’ve found a job!
Worth knowing (1)
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Two kinds of “so”
“So” that means “to such a degree” is not 所以 but 这么 (so … here, near me) or 那么 (so … there). Both stand directly before the adjective.
外面这么冷，你别出去了。It’s so cold outside — don’t go out.
The trap English speakers fall into
Watch out
English lets “therefore” wander into the middle of a clause (“I therefore stayed at home”), and learners carry that over. 所以 cannot move: it is a conjunction, it opens the result clause, and the subject comes after it.
Reason with yīnwèi first, result with suǒyǐ second — and suǒyǐ goes in front of the subject.
Your turn
9 exercises on this topic. Your answers are checked in the browser; none of them leaves your device.