I got a new bicycle from my father on my—————— (sixteen)birthday._英语解答

I got a new bicycle from my father on my—————— (sixteen)birthday.I like it very much.
正确形式填空,为什么sixteen要改为sixteenth

人气：138 ℃　时间：2019-10-24 14:11:45

解答

sixteenth
16岁生日,这是【第16个】年头了呀,表顺序,自然用序数词了这里的序数词是否相当于定语一样。。。。谢谢哦~~~本身就是定语。