2 sentences

1. 同学们正在操场上做操。

   tóng​xué​men zhèng​zài cāo​chǎng shàng zuò​cāo.

   The students are doing exercises on the playground.

   Source: Dong Chinese Dictionary

2. 清晨的校园里，学生们正在操场上做操。

   qīng​chén de xiào​yuán lǐ, xué​sheng men zhèng​zài cāo chǎng shàng zuò​cāo.

   In the early morning, students are doing exercises on the school playground.

   Source: Dong Chinese Dictionary