以为 (yǐwéi)

以为 is used when someone believes something that turns out to be wrong or different from reality. It implies a mistaken assumption, unlike 认为 (rènwéi) which is a neutral opinion.

Meanings

[verb] to think (incorrectly); to mistakenly believe; to assume (wrongly)

Example Sentences

我以为你不来了，没想到你来了。 Wǒ yǐwéi nǐ bù lái le, méi xiǎngdào nǐ lái le. I thought you were not coming; I did not expect you to show up.

他以为考试很简单，结果没通过。 Tā yǐwéi kǎoshì hěn jiǎndān, jiéguǒ méi tōngguò. He thought the exam was easy, but ended up failing.

我以为她是老师，原来她是学生。 Wǒ yǐwéi tā shì lǎoshī, yuánlái tā shì xuésheng. I thought she was a teacher; it turns out she is a student.

你以为我不知道吗？ Nǐ yǐwéi wǒ bù zhīdào ma? Did you think I did not know?

Collocations

Collocation	Meaning
我以为…	I thought (wrongly) that...
以为是	to mistakenly believe it was
没想到	unexpectedly (often follows 以为)
原来	it turns out (corrects 以为)

Memory Hook

以为 often appears before a surprise correction. Think: "I assumed... but actually..." Whenever you see 以为, expect the assumption to be wrong.