从【cóng】

从 marks where something starts, in space or in time. The 从 phrase goes before the verb.

从 belongs in front of the verb

English puts "from London" at the end of the sentence. Chinese puts it before the verb.

• × 我来从伦敦 → 我从伦敦来

从…到… for a span

The pair covers a distance or a stretch of time. Usually both halves come before the verb. When the 到 half says how far the action itself went, it can follow the verb instead: 从早上工作到晚上.

从 + a time + 开始 says when something starts.

从 or 离

从 is the starting point of a movement; 离 measures the gap between two fixed places. 从这儿到那儿 is a journey; 离这儿很远 is a distance.

• × 学校从我家很远 → 学校离我家很远

Asking where someone is from

你从哪儿来 asks where someone has come from – the journey, or the place they come from. 你是哪国人 asks only about nationality.