我以为你已经回家了，没想到你还在办公室。

Wǒ yǐwéi nǐ yǐjīng huí jiā le, méi xiǎngdào nǐ hái zài bàngōngshì.

I thought you had already gone home; I didn't expect you to still be in the office.

她以为今天不用上班，结果到了公司才发现搞错了。

Tā yǐwéi jīntiān bú yòng shàngbān, jiéguǒ dào le gōngsī cái fāxiàn gǎo cuò le.

She thought she didn't have to work today, but when she got to the company she realized she was wrong.

我以为这家店关门了，原来只是换了个地方。

Wǒ yǐwéi zhè jiā diàn guānmén le, yuánlái zhǐshì huàn le ge dìfang.

I thought this store had closed down, but it turned out it just moved to a different location.