在 + 草地 + 上
草地 (cǎodì) means 'grassland,' 'lawn,' or 'grassy area.' It combines 草 (grass) with 地 (ground/land). It can refer to anything from a park lawn to a meadow, as in 在草地上走路 (to walk on the grass).
孩子们在草地上开心地跑来跑去。
Háizimen zài cǎodì shàng kāixīn de pǎo lái pǎo qù.
The children were happily running around on the grass.
我们找了一块草地坐下来野餐。
Wǒmen zhǎo le yī kuài cǎodì zuò xiàlái yěcān.
We found a patch of grass and sat down for a picnic.
春天的草地绿油油的,特别漂亮。
Chūntiān de cǎodì lǜyóuyóu de, tèbié piàoliang.
The grass in spring is lush green and especially beautiful.