以…为…: take… as…
固定格式 / set structures
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
以 + A + 为 + B (主/中心/例/目标/荣…)
以 A 为 B (written) = "take A as B, regard A as B": the formal counterpart of 把 A 当作 B. Very frequent combinations:
• 以…为主: "mainly consist of" (以米饭为主).
• 以…为例: "take… as an example".
• 以…为中心 / 为目标 / 为荣: "centred on / aim at / be proud of".
Here 为 is read wéi (2nd tone), not wèi.
Examples
南方人的饮食以米饭为主。
Nánfāngrén de yǐnshí yǐ mǐfàn wéi zhǔ.Southerners' diet is mainly based on rice.
以北京为例，空气质量这几年明显改善了。
Yǐ Běijīng wéi lì, kōngqì zhìliàng zhè jǐ nián míngxiǎn gǎishàn le.Take Beijing: air quality has clearly improved in recent years.
这个城市以发展绿色能源为目标。
Zhège chéngshì yǐ fāzhǎn lǜsè néngyuán wéi mùbiāo.This city aims to develop green energy.
Common mistakes
✗ Reading 为 as *wèi*: here it's ✓ *wéi*.
✗ 以米饭是主 → ✓ 以米饭为主 (为 replaces 是 in writing).
✗ Using 以…为… in casual chat sounds stiff → ✓ 主要吃米饭。