In order to: 为了
介词 / prepositions
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
为了 + purpose，Subject + Verb… ｜ Subject + 是为了 + purpose
为了 (wèile) introduces the purpose of an action: "in order to, for the sake of". The 为了 + purpose phrase usually goes at the start: 为了保护环境，我们应该少开车。
You can also explain the purpose afterwards with 是为了: 我学中文，是为了去中国工作。
Keep 为了 (purpose, "in order to") apart from 因为 (cause, "because"): 为了健康 = to be healthy; 因为健康 = because one is healthy.
Examples
为了保护环境，我每天骑自行车上班。
Wèile bǎohù huánjìng, wǒ měi tiān qí zìxíngchē shàngbān.To protect the environment, I cycle to work every day.
为了节约用水，请随手关水。
Wèile jiéyuē yòng shuǐ, qǐng suíshǒu guān shuǐ.To save water, please turn off the tap after use.
我们种树是为了让空气更好。
Wǒmen zhòng shù shì wèile ràng kōngqì gèng hǎo.We plant trees to make the air better.
Common mistakes
✗ 我为了下雨没去。 → causes use 因为. ✓ 因为下雨，我没去。
✗ 我去中国为了学中文。 → in this order you need 是. ✓ 我去中国是为了学中文。