21的英文怎么写序数词

21的英文序数词twenty-first.

例句

Welcome to the twenty-first century.

欢迎进入21世纪。

Seventeen civilians were hurt. Most are students who had been attending a twenty-first birthday party.

17名平民受了伤，其中大多数是参加一个21岁生日聚会的学生。

The task facing medicine in the twenty-first century will be to redefine its limits even as it extends its capacities.

21世纪医学面临的.任务将是重新定义其限制，即使它扩大了其能力。

Geothermal energy probably will not make large-scale contributions to the world energy budget until well into the twenty-first century, if ever.

在进入21世纪之前，地热能可能不会对世界能源预算作出大规模贡献。

What defines a twenty-first-century entrepreneur?

21世纪创业者的特征有哪些？