昨天 + Verb Phrase
昨天 (zuótiān) means 'yesterday' and is one of the most basic time words in Chinese. It is placed before or after the subject to indicate that an action took place the day before today. Unlike in English, no preposition is needed — 昨天 functions directly as a time adverbial.
昨天下了一整天的雨,哪儿也去不了。
zuótiān xià le yì zhěng tiān de yǔ, nǎr yě qù bù liǎo.
It rained all day yesterday, so I couldn't go anywhere.
你昨天怎么没来上课?
nǐ zuótiān zěnme méi lái shàngkè?
Why didn't you come to class yesterday?
我昨天在超市碰到了一个老同学。
wǒ zuótiān zài chāoshì pèngdào le yí gè lǎo tóngxué.
I ran into an old classmate at the supermarket yesterday.