60-year-olds为什么Old会加上一个S?60-year-olds为什么Old会加上一个S,它和60 years old有什么区别?

60-year-olds为什么Old会加上一个S?60-year-olds为什么Old会加上一个S,它和60 years old有什么区别? 18 - to- 21- year-olds 为什么old加s sixteen-year-olds,old为什么加了s They were children.Four and five-year-olds,为什么old加s year olds还是years old? sixteen year olds 还是sixteen year old? eight-year-old和eight-year-olds后一个加了s也对吗? sisteen-year-olds的后面为什么要加s ____should not be alowed to go out at night.A.Twelve-years old B.Twelve-year-olds C.Twelve year old D.Twelve years olds选什么 为什么? I think ____should not drive anywhereA.sixteen-year-old B.sixteen-years-old C.sixteen-year-olds为什么 Sixteen-year-olds should be allowed drive.sixteen-year-old 是形容词,不应该加S的, sixteen-year-olds可以直接使用,sixteen-year-old不可以直接使用后面要加boy? six-year-old与six-year-olds的区别 15-year-old与15-year-olds的区别 sixteen -year -olds和sixteen -year -old有什么区别 year-olds与year-old的区别16-year-olds与16-year-old有什么区别吗? 单选I think___shouldnot be allowed to drive.A.sixteen-year-old B.sixteen-year-olds 为什么选B, 为什么six-year-olds 是正确的