In Mandarin Chinese, the translation for "last year" is qù nián. Since qù means "to go", this is literally "the year that has gone", which makes perfect sense. But "last month" and "last week" are shàng gè yuè and shàng gèxīng qī respectively, or "the above month" and "the above week". I don't know why the scheme is different. Perhaps "above" refers to the position of months and years on a calendar.