1号 first
2号 second
3号 third
其他的加th
但注意如果数字中以1，2，3结尾，比如21，22，23，也要分别用st, nd, rd
---------------------------------------------------------------------------------------------------
1st 2nd 3rd 4th 5th 6th 8th 9th 10th
11st 12nd 13rd 14th 15th 16th 18th 19th 20th
21st 22nd 23rd 24th 25th 26th 28th 29th 30th 31st
------------------------------^^--^^---------------------------------------