At the age of around twenty nine, Saturn returns to its position at the time of birth, and this stage is seen as an important milestone in a person's life.

在大约二十九岁的时候，土星回归到出生时候的位置，这个阶段被视为是一个人生命中一个重要的里程碑。

youdao

This marks an important milestone in my goal to create a cleaner cab fleet, firstly through introduction of the first ever age limits moving towards zero-emission vehicles as they come to market.

ENGADGET: UK's first fuel cell-powered black cab hits the streets of London

For readers of a certain age (the classic form of the catalogue was phased out in 1993), it was an annual milestone.

FORBES: Magazine Article