Before a specific time with "yiqian"

As well as talking about the past in general, you can use 以前 (yǐqián) to talk about things that happened before a specific time.

Structure

Time + 以前， Subject + Verb + Object

Verb + 以前， Subject + Verb + Object

The time can be a specific time, or an action (technically, "when the action was done").

十点 以前，我在家。 Shí diǎn yǐqián, wǒ zài jiā. I will be at home before ten o'clock.
上大学 以前，我不会说中文。 Shàng dàxué yǐqián, wǒ bù huì shuō Zhōngwén. Before I attended college, I couldn't speak Chinese.
三点 以前，我在咖啡店。 Sān diǎn yǐqián, wǒ zài kāfēidiàn. Before three o'clock, I'll be in the coffee shop.
睡觉以前，你不能吃糖。 Shuìjiào yǐqián, nǐ bù néng chī táng. Before going to sleep, you can't eat sugar.
星期五 以前，要做完你的工作。 Xīngqī wǔ yǐqián, yào zuò wán nǐ de gōngzuò. Before Friday, you need to finish your work.
开会以前，我们要有一个计划。 Kāihuì yǐqián, wǒmen yào yǒu yīgè jìhuà. Before the meeting, we need a plan.
三年 以前，我来到了上海。 Sān nián yǐqián, wǒ lái dào le Shànghǎi. Three years ago I came to Shanghai.
吃饭 以前，你应该洗手。 Chī fàn yǐqián, nǐ yīnggāi xǐ shǒu. Before eating, you should wash your hands.
一个月 以前，我认识了我的老婆。 Yī gè yuè yǐqián, wǒ rènshi le wǒ de lǎopó. A month ago I met my wife.
生孩子 以前，你应该先结婚。 Shēng háizi yǐqián, nǐ yīnggāi xiān jiéhūn. Before having kids, you should first get married.