★ remnant（n）（常做复数）事物或人剩余的小部分，余下的数量；遗留的痕迹
The Ainu settlers in Hokkaido are the last remnant of a prehistoric race.
北海道的阿伊努人是史前某个种族的最后残存者。
I will sell this remnant to you, at cost.
我愿将此剩货照成本卖给你。
the remnants of a shattered army 被击溃的军队残余部分
remnants of one’s former glory自己过去的光荣见证
★ residue（n）（通常做单数）剩余物，残余
The residue includes heavy metals, carcinogens and even radioactive materials that young children can get on their hands and ingest, especially if they're crawling or playing on the floor.
残留物包含重金属、致癌物，甚至辐射物质，它们很容易沾在婴幼儿的手上并被吃到嘴里，尤其是当小孩子在地板上爬或玩耍时。