0 having a wrong idea of what is likely to happen or of what you can really do; not based on facts -- 不切實際的;不實事求是的;不現實的
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。