It's the phosphate and the pentose that make up the backbone - that make up the upright struts of the ladder and it's the bases that make up the connecting struts, so the bases are the colors.

磷酸基和戊糖,共同构成了主链,主链又构成了梯子上下的支柱,而碱基,则构成连接支柱的梯阶,碱基是用各种颜色表示的

耶鲁公开课 - 生物医学工程探索课程节选

The consolation is they're killing people at the top too so they're going to so when you do get a job in a financial institution there will be more spaces above you on the ladder to move up.

慰藉就是，他们同样也在高层解雇人,所以他们将会,当你在一家金融机构找到工作后,你会有很大的晋升空间。

耶鲁公开课 - 金融市场课程节选