11th还是11st为什么?为什么?

11th还是11st为什么?为什么? 11号英语怎么表达 是11st 还是11th 为什么练习册上的是11st 英语日期11号也要st吗是st还是th? 关于日期“st与”th的解释为什么用英文写日期有时用“st”有时用“th”?有时就12st，有时就11st，有时就26th,有时就25th，为什么，（我是学生，看到老师的写法后才怀疑的） 带解释最好） 第十一是11th还是11st,12和13呢 11日英文简写后面到底是st还是th帮个忙●﹏● 1st,2nd,3rd,4th,5th,6th,7th,8th,9th,10th,11th, 英语序数词中的11,12,13后边为什么加th,而21,22,23的后边加st,nd,rd呢? 英文日期缩写 这样对?1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th ； 11th 12th 13th 14th 15th 16th 17th1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th ； 11th 12th 13th 14th 15th 16th 17th 18th 19th 20th ； 21st 22nd 23rd 24th 25th 26th 27th 28th 29t 请问下21日应该写成21th,还是21st 11和21也是要按照1st这样去写么. 11th St.RANCHOCUCAMONGA,CA是加州什么地方 英语年月日的书写?为什么oct.1st,2009,1后面加st,但有时加th呢?是怎么回事? 那位人士帮我把8th 9th 11th 12th 20th 13th 21st写出原型? first 1st second 2nd twenty-first 21st one hundred and first 101st 为什么它们的结尾不是“什么th”? 为什么英文表达日期1-28日后面加TH 而30-31后面加ST 我想问在几号后面应该加th,nd,rd,st.12号要加nd还是th啊?为什么?23号后面是加什么?22号后面又是加什么? 英语翻译1st.2nd.3rd.4th.5th.6th.7th.8th.9th.10th.11th.-----20th21st,22nd,23rd24----30th31st英文翻译,比如30th是“thirtieth” 为什么my birthday is February 11th,可以不用加on,在when is the volleyball game?It's on January 1st要加on呢?请说明理由和方法.