5 sentences

1. 这颗彗星的运行轨迹非常特殊。

   zhè kē huì​xīng de yùn​xíng guǐ​jì fēi​cháng tè​shū.

   The trajectory of this comet is very unusual.

   Source: Dong Chinese Dictionary

2. 每个人的成长轨迹都是独一无二的。

   měi gè rén de chéng​zhǎng guǐ​jì dōu shì dú​yī​wú'èr de.

   Everyone's growth trajectory is unique.

   Source: Dong Chinese Dictionary

3. 天文学家正在观测木卫一的运动轨迹。

   tiān​wén​xué​jiā zhèng​zài guān​cè Mù​wèi Yī de yùn​dòng guǐ​jì.

   Astronomers are observing the trajectory of Io.

   Source: Dong Chinese Dictionary

4. 家中突遭变故，他的生活轨迹彻底改变了。

   jiā zhōng tū zāo biàn​gù, tā de shēng​huó guǐ​jì chè​dǐ gǎi​biàn le.

   A sudden misfortune in his family completely changed the course of his life.

   Source: Dong Chinese Dictionary

5. 圆是平面上到定点距离等于定长的点的轨迹。

   yuán shì píng​miàn shàng dào dìng​diǎn jù​lí děng​yú dìng​cháng de diǎn de guǐ​jì.

   A circle is the locus of points in a plane that are at a fixed distance from a fixed point.

   Source: Dong Chinese Dictionary