YOU SAID:

She sells seashells by the sea shore the shells she sells are surely seashells so if she sells sea shore shells then surely she sells shell seashores

INTO JAPANESE

彼女は海岸で貝殻を売っている 彼女が売っている貝殻は間違いなく貝殻なので、彼女が海岸の貝殻を売るなら、きっと彼女は貝殻の海岸を売っているでしょう

BACK INTO ENGLISH

She sells seashells on the seashore The seashells she sells are definitely seashells, so if she sells seashells on the seashore, she's probably selling seashells on the seashore

INTO JAPANESE

彼女は海岸で貝殻を売っています 彼女が売っている貝殻は間違いなく貝殻です、だから彼女が海岸で貝殻を売っているなら、彼女はおそらく海岸で貝殻を売っているでしょう

BACK INTO ENGLISH

She sells seashells on the seashore The seashells she sells are definitely seashells, so if she sells seashells on the seashore, she's probably selling seashells on the seashore