Researchers studying the effects of long-term spaceflight often examine the hipbone or backbone.

VOA: special.2009.03.10

He is independent in a way that nobody who was not a king or an aristocrat in the past has ever been -- a new kind of man, the backbone of the polis as it emerges.

他是如此的独立以至于,前无古人后无来者,一个全新的人,它不断地发展并成为城邦制的脊梁

耶鲁公开课 - 古希腊历史简介课程节选

Every unit in the backbone of this ladder has the same sugar unit, the same pentose; it's either RNA or DNA and has ribose or deoxyribose, so you don't need to describe the whole thing.

主链的每个单位,都由相同的糖单位构成,同样的戊糖,RNA里是核糖,DNA里是脱氧核糖,所以你不需要所有细节都描述

耶鲁公开课 - 生物医学工程探索课程节选