four-year-old为什么year不用复数形式

four-year-old为什么year不用复数形式 four-year-old和four year old有什么不同 only four year old意思 a four-year-old boy可以说成a four-year old boy They were children.Four and five-year-olds,为什么old加s This is a_boy.He can't look after himself A,four-years-old.B.four-years-olds,C,four- year-old为什么 my father is---------- (four) year old后面是单数 four-year-old和middle-aged 杠表示是什么? This____girl is so lovely.A.four years old B.four-years-girl C.four-year-old D.six-months-old My nine-year-old daughter,Maria,is in Year Four.怎么翻译 关于four－year－old－－－children are too young to go to schoolA four－year－oldB four－years－oldC four years oldD four year old答案是A．为什么A是对的?为什么C不对?麻烦分析一下 为什么 a four-year-old boy中的year可以不加复数,而分数two-thirds中连字符后的third就必须有s? although和BUTHE CAN DRAW VERY WELL（）HE IS ONLY A （）BOYA THOUGH FOUR-YEAR-OLD B BUT FOUR-YEARS-OLDC ALTHOUGH FOUR-YEARS-OLD此题最多2个答案.说出答案时要写为什么这个答案 为什么12-year-old=12 years old 英语翻译还有,“他四岁”是说he is four years old还是he is four year old? 请问:是a four years old boy?还是a four year old boy?正确要肯定的 my gaughter four years old这句是不少is?等与my four-year-old daughter?Thank you! year old,year-old,years old,years-old的区别