0 below an average or expected standard, especially of intelligence -- 低于正常标准的,低下的;(尤指)弱智的,低能的
mentally subnormal 心智低下的
subnormal temperatures 低于正常水平的气温
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。