twenty-one
英 [ˈtwenti wʌn] 美 [ˈtwenti wʌn]
num.二十一
n.二十一，二十一个所成之一组;二十一点牌戏（一种赌博游戏）
例句：
1.The diet is chosen under a franchise that is universal for citizens aged twenty-one and over.
国会由年满二十一岁以上的公民普遍选举产生。
2.On each of the factors were fine research, twenty-one indexes were obtained.
对每个因素进行精细化研究，共得出二十一个指标。
3.We waited twenty-one years, don't fail us now.
我们等了21年了，如今不要让我们失望。
4.Winterton has never had a sniff of a government job in his entire twenty-one years in parliament.
在国会的整整21年里，温特顿没有得到过任何在政府里工作的机会。
