单选题

　　【阅读选择】It normally takes from five days to one week for a person to adapt to a reversed routine of sleep and wakefulness, sleeping during the day and working at night. Unfortunately, it is often the case in industry that shifts are changed every week; a person may work from 12 midnight to 8 a. m. one week, 8 am to 4pm the next, and 4 pm to 12 midnight the third and so on. This means that no sooner has he got used to one routine than he has to change to another, so that much of his time is spent neither working nor sleeping very efficiently. In the last sentence of the paragraph, “another” means_____.

　　A、another routine

　　B、another shift

　　C、another week

　　D、another person