18 years old和18-years-old有什么区别

My feiend is 18 years old this year.(对“18 years old ”提问) Mrs Green is a doctor of______and her daughter Ann is_____university sthdentA.50 years old;an 18-year-old B.50-year-old;an 18 years old C.50 years old;a 18-years-old D.50-years he is 18 years old.为什么year要加S 18 years old和18-years-old有什么区别 years old 和year-old的区别和用法 Jane is（）high school studentA.a 18-year-old B.a 18-years-old C.an 18-years-old D.an 18-year-old year old,year-old,years old,years-old的区别 fourteen year old和fourteen years old和fourteen-year-old和fourteen-years-old的区别 ten years old 和ten-year-old的区别 three-year-old 和 three years old 有什么区别 three -year-old 和 three years old有什么区别? 11-year-old和11 years old有什么区别 seven years old和even-year-old的区别 12 -year-old 和12 years old的区别 an 18 years old,an 18-year-old有什么区别 1、be careful ____ _____ ____ (not play)with matches.2、Simon is an _____ boy .it means he is ____ A.18 years old;18 years old B .18-year-old;18 years old C.18 years old;18-year -old D.18-year-old;18-year-old six years old 和 six- year- old 和 six- year- olds的区别如题 16-year-old和16-year-olds和16 years old有什么区别?