verb · to lay a foundation or a base for future development

这些基础课程是为以后的专业学习垫底。

verb, adjective · to be at the very bottom of a ranking or competition

他在这次模拟考试中成绩不幸垫底。

verb · to eat a small amount of food to prevent hunger before a main meal

离晚饭还有两小时，你先吃个包子垫底。

verb · to put something on the bottom or underneath for protection or support

他在箱子下面铺了几层厚纸来垫底。