0 the distance of a place east or west of an imaginary line between the North Pole and the South Pole, measured in degrees -- 經度
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。