wǒ zuówǎn zài jiā.

I

Breakdown of wǒ zuówǎn zài jiā.

• 在zài: to be at
• 家jiā: home
• 昨晚zuówǎn: last night

Questions & Answers about wǒ zuówǎn zài jiā.

Why is there no word for am/was in this sentence?

Because Mandarin does not use a verb like English to be for location in this kind of sentence.

In 我昨晚在家, the word 在 is doing the job of be at / be in / be located at.

So:

• 我 = I
• 昨晚 = last night
• 在家 = at home

A very natural English translation is I was at home last night, even though there is no separate word meaning was.

What exactly does 在 mean here?

Here, 在 means to be at, to be in, or to be located at.

It is important not to confuse this with another common use of 在, where it marks an ongoing action, as in 我在吃饭 (I am eating).

In 我昨晚在家, 在 is the main verb of the sentence:

• 我在家 = I am at home
• 我昨晚在家 = I was at home last night

Why isn’t 是 used here?