springboard
n
1 strong flexible board from which a person can jump high before diving or performing a gymnastic feat (跳水运动的)跳板; (体操运动的)踏跳板.
2 ~ (to/for sth) (fig 比喻) starting point that gives impetus to a future activity 发展事业的起点
The college debating society was a natural springboard for her career in politics. 大学里的辩论社自然成了她从政的垫脚石.