Tā yǐjīng liùqīshí suì le, dàn shēntǐ hái hěn yìnglǎng.
She's already in her sixties or seventies, but she's still in great shape.
Tips
grammar
Chinese expresses 'approximately N or N+1' simply by stringing two adjacent numbers together: 三四 'three or four', 五六 'five or six', 六七十 'sixty to seventy', 两三百 'two or three hundred'. No connective like 'or' is needed - adjacency does the work.
usage
Frequently followed by 岁 for age estimates, 个 for rough counts of people or items, and 块 for casual price ranges (六七十块 'sixty or seventy kuai').
