Supplementary things are added to something in order to improve it. 补充的
adjective [原级] 补充的，附加的；（角）互补的
...the question of whether or not we need to take supplementary vitamins. …我们是否有必要补充维生素的问题。
noun [物质名词] 补充者，增补物；<英>补充提问
Its designers were not high-end with supplementary lines. 它的设计师们不是高端产品的补充线。
