B1
於是, 因此 and 結果 — and so, therefore, in the end
Four Chinese ways of introducing a consequence, what each adds beyond 所以, and why 於是 cannot pair with 因為.
所以 is the everyday word for so and covers most of what you need. These three sit alongside it, and each carries something 所以 does not.
於是 — and so, at that point
Narrative. One thing happened, and as a direct result the next thing happened. It moves a story forward rather than explaining anything.
天太晚了，於是我們就回家了。
Tiān tài wǎn le, yúshì wǒmen jiù huí jiā le.
It was getting late, so we went home.
沒有人接電話，於是他自己去了。
Méiyǒu rén jiē diànhuà, yúshì tā zìjǐ qù le.
Nobody answered, so he went himself.
於是 often has 就 with it, which is the same 就 as elsewhere — one thing following straight on from another.
因為下雨，於是我們沒去。
因為下雨，所以我們沒去。
於是 follows a narrated event, not a stated cause. 因為 announces that a reason is coming, and the word that answers it is 所以.
因此 — therefore
Formal and logical. A conclusion drawn, rather than an event that followed. You will read it far more than you will say it.
他沒準備，因此沒通過考試。
Tā méi zhǔnbèi, yīncǐ méi tōngguò kǎoshì.
He hadn’t prepared, and therefore didn’t pass.
因而 and 從而 are near neighbours, both written, and not worth separating until you are reading a lot of formal prose.
結果 — as it turned out
The outcome, usually one nobody wanted. 結果 carries a small sense of anticlimax or surprise, which is why it so often introduces bad news.
我們等了兩個小時，結果他沒來。
Wǒmen děngle liǎng ge xiǎoshí, jiéguǒ tā méi lái.
We waited two hours and in the end he didn’t come.
我準備了很久，結果沒用上。
Wǒ zhǔnbèile hěn jiǔ, jiéguǒ méi yòngshàng.
I prepared for ages and never needed any of it.
結果 is also an ordinary noun meaning result — 考試結果 — and the connective use grew from it.
Which to reach for
- 所以 — always available, and right nine times out of ten
- 於是 — telling a story, and this is what happened next
- 因此 — writing, and this follows logically
- 結果 — and it turned out like this, which you were not expecting