一来…二来【yīlái…èrlái】

一来…二来 gives two reasons behind one decision or situation, each opening its own clause. It works in speech and writing.

The result can come before the reasons or after them. After them, 所以 or 就 often marks it. A third reason takes 三来.

Two purposes

The same frame lists two aims for one action: "partly to …, partly to …".

Reasons, not steps

一来…二来 only lists reasons and purposes. For actions in order, use 先…然后 or 首先…其次.

• × 一来洗手，二来吃饭 → 先洗手，然后吃饭