YOU SAID:
people sleep at day and play at night
INTO JAPANESE
人々は昼は寝て夜は遊ぶ
BACK INTO ENGLISH
People sleep during the day and play at night
INTO JAPANESE
人々は日中は眠り、夜は遊ぶ
BACK INTO ENGLISH
People sleep during the day and play at night
That didn't even make that much sense in English.