N-COUNT [usually singular]缺少的环节(指为完全理解某事尚需知道的一则信息或证据) The missing link in a situation is the piece of information or evidence that you need in order to make your knowledge or understanding of something complete. 缺少的环节(指为完全理解某事尚需知道的一则信息或证据)
We're dealing with probably the biggest missing link in what we know about human evolution.