And so (consequence) with 于是

Structure (situation)，于是 + next action

于是 (yúshì) links a situation to the action taken next, in a narrative: "(this happened), so (I did that)". 下雨了，于是我们没去 = "it started raining, so we didn’t go". Unlike 所以 (logical cause→effect), 于是 marks the SEQUENCE of events in a story.

Examples

天tiān黑hēi了le，于yú是shì我wǒ们men回huí家jiā了le。
It got dark, so we went home.
他tā病bìng了le，于yú是shì没méi来lái上shàng班bān。
He fell ill, so he didn’t come to work.
下xià雨yǔ了le，于yú是shì我wǒ们men没méi去qù。
It started raining, so we didn’t go.

Levels are indicative: they follow the standard Chinese Grammar Wiki (AllSet Learning) progression, not an official HSK 3.0 mapping. We never assign levels by eye.

This point and the other 370, with audio on every example, inside Wanyu.