YOU SAID:
She sells sea shells on a sea shore.
INTO JAPANESE
彼女は海岸で貝殻を売っている。
BACK INTO ENGLISH
She sells seashells on the beach.
INTO JAPANESE
彼女はビーチで貝殻を売っている。
BACK INTO ENGLISH
She sells seashells on the beach.
That didn't even make that much sense in English.