一. 21st 22nd 23rd 24-29后面都是加th 如24th 25th等
31st 32nd 33rd 34-39后面也都是加th
41st 42nd 43rd 44-49后面也都是加th
二. one two three four five six seven eight nine ten (1-10)
eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen (11-19)
twenty twenty-one twenty-two twenty-three twenty-four twenty-five twenty-six twenty- seven twenty-eight twenty-nine (20-29)
thirty thiry-one thirty-two thirty-four thirty-five thirty-six thirty-seven thirty-eight thirty-nine(30-39)
forty foty-one forty-two forty-three forty-five forty-six forty-seven forty-eight forty-nine(40-49)
温馨提示：答案为网友推荐，仅供参考