The correct answer is A.
Nǐ zhǔnbèi shénme shíhou jiéhūn?
Tina：你 准备 什么 时候 结婚？
When are you going to get married?
Sānshí suì yǐqián kěndìng jiéhūn.
Kate：三十 岁 以前 肯定 结婚。
I plan to get married before I’m 30 years old.
Explanation:
This test aims to bring attention to the differences between 以前 (yǐqián) and 从前 (cónɡqián). The differences are as follows:
1. 从前 (cónɡqián) always refers to a time far in the past, while 以前 (yǐqián) is closer to the present.
Examples:
Cóngqián, yǒu yíge shīrén jiào Lǐ Bái.
从前， 有 一个 诗人 叫 李 白。
Once, there was a poet named Li Bai.
Yǐqián, wǒ zhùzài zhōngguó.
以前， 我 住在 中国。
Previously, I lived in China.
2. 以前 (yǐqián) can be used after time words while 从前 (cónɡqián) cannot.
Examples:
Tiānliàng yǐqián, wǒ bìxū qǐchuáng.
天亮 以前，我 必须 起床。
Before dawn, I must get up.
Tā shísuì yǐqián zhù zài Běijīng.
他 十岁 以前 住 在 北京。
Before he was ten years old, he lived in Beijing.
In the earlier conversation between Tina and Kate, 三十岁 (sānshísuì) is considered to be a time phrase, so this makes 以前 (yǐqián) the correct choice.
3. 以前 (yǐqián) refers generally to a time before now, and it can be placed at the beginning or the middle of a sentence.
Examples:
Yǐqián, wǒ zài xiǎoxué jiāoshū.
以前， 我 在 小学 教书。
Previously, I taught at a primary school.
Wǒ yǐqián zài xiǎoxué jiāoshū.
我 以前 在 小学 教书。
I used to teach at primary school.
4．从前 (cónɡqián) is always used at the very beginning of a story. It is similar to the English phrase “a long time ago,” or “once upon a time.”
Example:
Cóngqián, sēnlín lǐ zhùzhe yíwèi lièrén.
从前， 森林 里 住着 一位 猎人。
A long time ago, there lived a hunter in the forest.
