YOU SAID:
The girl ran, playing in the grass.
INTO JAPANESE
女の子は草の上で遊びながら走りました。
BACK INTO ENGLISH
The girl ran and played on the grass.
INTO JAPANESE
女の子は芝生の上を走って遊んだ。
BACK INTO ENGLISH
The girl ran and played on the grass.
That didn't even make that much sense in English.