戴尔，莫俐教美语 9 美式英语各年龄段的叫法

Fetus (Unborn), Newborn (Birth - 1 month), Baby (1 month and 1 day - 2 years), Toddler (3 - 5), Kid (6 - 9),
Pre-Teen (10 - 12), Teenager (13 - 17), Young Adult (18 - 20), Adult (21 - 39), Young Middle-Aged Adult (40 - 49),
Middle-Aged Adult (50 - 54), Very Young Senior Citizen (55 - 64), Young Senior Citizen (65 - 74),
Senior Citizen (75 - 84), Old Senior Citizen (85+)