以为 (mistakenly think that)

• Pinyin: yǐwéi
• Formation: Subject + 以为 + Clause
• Hanzi breakdown: 以 = a pictograph of a person carrying something; 为 = simplified from 為, originally depicting a hand leading an elephant

Meaning

The verb 以为 means 'to mistakenly think' or 'to assume (incorrectly).' It introduces a belief that the speaker or someone else held but that turned out to be wrong.

Unlike 认为 (to think/believe) and 觉得 (to feel/think), which are neutral about correctness, 以为 inherently implies the belief was mistaken. It is often paired with a follow-up clause showing what actually happened, frequently introduced by 原来 (it turns out), 其实 (actually), or 没想到 (didn't expect). For example: 我以为他是中国人，原来他是日本人 (I thought he was Chinese, but it turns out he's Japanese). This pattern is essential in storytelling and daily conversation. Some speakers also use 以为 sarcastically to challenge someone else's assumption.

Examples

1. 我以为你已经回家了，原来你还在办公室。 I thought you had already gone home, but you're still in the office.
2. 他以为今天不用上班，结果迟到了。 He thought he didn't have work today, and ended up being late.
3. 她以为这道题很简单，没想到做错了。 She thought the question was easy, but unexpectedly got it wrong.

Usage Guide

Context: spoken, written, everyday

Tone: corrective

Do Say

• 我以为这家店很贵，其实价格很合理。
• 大家以为她会放弃，没想到她坚持到了最后。
• 别以为学中文很容易，其实需要很多练习。

Don't Say

• 我以为这本书很好看。(If the belief is still held and hasn't been proven wrong, use 觉得 or 认为 — 以为 implies the belief was mistaken) → 我觉得这本书很好看。
• 他以为了她是老师。(以为 is a verb that directly takes a clause — do not insert 了 between 以为 and the clause) → 他以为她是老师。

Origin & History

以 means 'to use' or 'to take as' and 为 means 'to be' or 'to consider.' Together 以为 literally means 'to take as being,' which naturally lends itself to the idea of mistaken assumption.

Cultural Context

Generation: All ages

Social background: Universal