2 sentences

1. 孩子们在草地上无忧无虑地玩耍。

   hái​zi men zài cǎo​dì shàng wú​yōu​wú​lǜ de wán​shuǎ.

   The children are playing carefree on the grass.

   Source: Dong Chinese Dictionary

2. 老同学聚会时，大家一起缅怀那段无忧无虑的校园时光。

   lǎo tóng​xué jù​huì shí, dà​jiā yī​qǐ miǎn​huái nà duàn wú​yōu​wú​lǜ de xiào​yuán shí​guāng.

   At the reunion, old classmates reminisced about their carefree school days.

   Source: Dong Chinese Dictionary