YOU SAID:
she sell seashell by the seashore
INTO JAPANESE
彼女は海岸で貝殻を売っています
BACK INTO ENGLISH
She sells seashells on the shore
INTO JAPANESE
彼女は海岸で貝殻を売っています
BACK INTO ENGLISH
She sells seashells on the shore
That didn't even make that much sense in English.