3 sentences

1. 我又回到原点了。

   wǒ yòu huí​dào yuán​diǎn le.

   I'm back to where I started.

   Source: OpenSubtitles

2. 如果这个计划失败了，我们就必须回到原点重新开始。

   rú​guǒ zhè​ge jì​huà shī​bài le, wǒ​men jiù bì​xū huí​dào yuán​diǎn chóng​xīn kāi​shǐ.

   If this plan fails, we must go back to square one and start over.

   Source: Dong Chinese Dictionary

3. 在直角坐标系中，原点的坐标通常表示为(0,0)。

   zài zhí​jiǎo zuò​biāo​xì zhōng, yuán​diǎn de zuò​biāo tōng​cháng biǎo​shì wéi(0,0).

   In a Cartesian coordinate system, the coordinates of the origin are usually represented as (0,0).

   Source: Dong Chinese Dictionary