YOU SAID:
She fell from a tree into a well that was not well-covered
INTO JAPANESE
彼女は木から落ちて、よく覆われていない井戸に落ちました
BACK INTO ENGLISH
She fell from a tree and fell into a well-covered well
INTO JAPANESE
彼女は木から落ちて、よく覆われた井戸に落ちました
BACK INTO ENGLISH
She fell from a tree and fell into a well-covered well
That didn't even make that much sense in English.