the ninetieth第九十
th ninetieth第九十
Enter Ninetieth第九十天
ninetieth anniversary周年
ninetieth 90th第
my ninetieth birthday我第九十岁生日;我的九十岁生日;我国九十大寿
On His Ninetieth Birthday当九十岁来临时;九十岁生日演讲美国
ninetieth-eighth第九十八
grandpa is ninetieth birthday爷爷是九十大寿;爷爷是九十岁生日
ORD（序数词） The ninetieth item in a series is the one that you count as number ninety. 第90
He celebrates his ninetieth birthday on Friday.
他周五庆祝他的90岁生日。