2 sentences

1. 老同学聚在一起，共同重温昔日的校园生活。

   lǎo tóng​xué jù zài​yī​qǐ, gòng​tóng chóng​wēn xī​rì de xiào​yuán shēng​huó.

   Old classmates gathered together to reminisce about their school days.

   Source: Dong Chinese Dictionary

2. 在开始高级课程之前，我们需要重温一下基础知识。

   zài kāi​shǐ gāo​jí kè​chéng zhī​qián, wǒ​men xū​yào chóng​wēn yī​xià jī​chǔ zhī​shi.

   Before starting the advanced course, we need to review the basic knowledge.

   Source: Dong Chinese Dictionary