0 a person who changes from one opinion to an opposite one in a way that shows they are not loyal to people who share the original opinion -- 变节者,叛徒
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
再长的路,一步步也能走完,再短的路,不迈开双脚也无法到达。