YOU SAID:

i look for a difficult sentence with my mother's son's arm's finger's on my own keyboard

INTO JAPANESE

私は母の息子の腕と指を使って自分のキーボードを使って難しい文を探します

BACK INTO ENGLISH

I use my mother son arm and fingers to find difficult sentences using my keyboard

INTO JAPANESE

母と息子の腕と指を使って、キーボードを使って難しい文章を見つけます

BACK INTO ENGLISH

Mother and son use arms and fingers to find difficult sentences using keyboard

INTO JAPANESE

母と息子は腕と指を使い、キーボードを使って難しい文章を見つけます

BACK INTO ENGLISH

Mother and son use arms and fingers to find difficult sentences using keyboard