踏み台を英語でなんと言うか？

一般に踏み台（踏み切り板、ロイター板、跳躍代）はspringboardで言いあらわせますが、日本語の解釈は叩き台となる場合もあります。0:53 we make rooms for contemporary taste but often use history as a springboard. 部屋を現代風にアレンジするが、歴史を叩き台にすることもある。

http://www.youtube.com/watch?v=jCt-QRdbLH4 0:31 Frederique covered Cosmopolitan and Harper’s Bazaar during the '80s and later used her success as a springboard for various projects.
http://www.youtube.com/watch?v=xW2gyj_KWqg 5:23 in May 2011, a different scandal served as a springboard for her career.
http://www.youtube.com/watch?annotation_id=annotation_505943&feature=iv&src_vid=tMAC0ZZxZC4&v=gfEgE3XMYBk 53:41 perhaps one day the Moon will become a springboard for exploring the Solar system.
https://www.youtube.com/watch?v=-hmplTLKDNA  0:18 now concern is stirring that migrants using Greece as a launchpad to head into the more prosperous western Europe could end up stranded in the impoverished country.
Migrant hope and despair in Greece