Grammar Point:The terms 以前 yǐqián (before) and 以後后 yǐhòu (after) are Chinese expressions used to indicate time references. Here’s an explanation of their grammar and usage: 以前 yǐqián Time or Verb + 以前 (Before) 你nǐ明天míngtiān8 點diǎn以前yǐqián必須bìxū到dào公司gōngsī你nǐ明天míngtiān8 点diǎn以前yǐqián必须bìxū到dào公司gōngsīYou must arrive at the company before 8 o’clock tomorrow. 我wǒ知道zhīdào我wǒ在zài做夢zuòmèng, 但是dànshì我wǒ希望xīwàng50 歲suì以前yǐqián能néng退休tuìxiū我wǒ知道zhīdào我wǒ在zài做夢zuòmèng, 但是dànshì我wǒ希望xīwàng50 岁suì以前yǐqián能néng退休tuìxiūI know I’m dreaming, but…