This material will be necessary to do the listening exercises for the course, which is sort of the backbone of the course.

做听力练习时我们必须使用这些材料,听力训练是课程的核心内容

耶鲁公开课 - 聆听音乐课程节选

One thing to notice is this part of the double helix that we'll call the backbone.

要注意的是,这两股构成双螺旋的链我们称之为主链

耶鲁公开课 - 生物医学工程探索课程节选

So what's going to form the backbone is this continual link, phosphate to sugar, phosphate to sugar, phosphate to sugar, all linked together to form one long, long molecule.

主链是由这样重复的连接构成的,从磷酸到戊糖,周而复始,所有这些连接起来构成一个长链分子

耶鲁公开课 - 生物医学工程探索课程节选