0 the 13th letter of the English alphabet -- （英语字母表的第13个字母）
1 the sign used in the Roman system for the number 1,000 -- （罗马数字）1000
2 (in the UK and Ireland) abbreviation for motorway -- （英国和爱尔兰）高速公路（motorway的缩写）
The M4 goes from London to Bristol. 4号高速公路连接伦敦和布里斯托尔。
3 written abbreviation for medium adjective(MIDDLE) : used on clothes to show that they are of medium size -- （服装尺寸）中号（medium的缩写）
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。
