从…中【cóng … zhōng】

从 + noun + 中 marks something as coming out of that noun. The noun is usually abstract – an experience, a mistake, a book, a conversation – and the verb is about gaining: 学, 学到, 得到, 看出, 发现. It's neutral to written.

With 看出 or 听出, it says what you could tell from something.

Choosing from a group

With 选, 挑 and similar verbs, the noun is a set to pick from.

从中

When the source has just been mentioned, 从中 stands for "from it".

Don't drop 中

With an abstract noun, 从 alone sounds unfinished. 中 (or 里, in speech) closes the phrase.

• × 从失败学到很多 → 从失败中学到很多

The whole phrase goes before the verb, not after it as in English.

• × 我们学习从错误中 → 我们从错误中学习