sixteen-year-olds,old为什么加了s

sixteen year olds 还是sixteen year old? sixteen -year -olds和sixteen -year -old有什么区别 sixteen-year-olds能做主语吗? sixteen-year-olds 这种表达正确么? sixteen-year-olds单数还是负数 Sixteen-year-olds什么词性 sixteen years old 什么词性 sixteen year old、sixteen-year-olds、sixteen-year-old有什么区别 sixteen-years-old与sixteen years old有什么区别sixteen year olds与sixteen-year-old都是什么时候用 sixteen-year-olds,old为什么加了s 16岁的男孩们 英语怎么说sixteen-year-olds boy和sixteen-year-old boys哪个对?还有sixteen-year-olds对么？ I think ( ) should not be allowed to drive.A sixteen years old B sixteen-year-old C sixteen-year-olds I think ____should not drive anywhereA.sixteen-year-old B.sixteen-years-old C.sixteen-year-olds为什么 单选I think___shouldnot be allowed to drive.A.sixteen-year-old B.sixteen-year-olds 选什么 Sixteen-year-olds should be allowed drive.sixteen-year-old 是形容词,不应该加S的, 单选I think___shouldnot be allowed to drive.A.sixteen-year-old B.sixteen-year-olds 为什么选B, sixteen-year-olds可以直接使用,sixteen-year-old不可以直接使用后面要加boy? ▁▁▁shouldn’t be allowed to go swimming in the river alone.A.Sixteen-year-oldB.Sixteen-years-oldC.Sixteen-year-olds 16岁 英语 怎么说是 sixteen-years-old还是sixteen-year-olds?还有 不加一横的？越来越混乱了