为什么year old是放在一起的,i am ten old this year

为什么year old是放在一起的,i am ten old this year [英语]两个介词放在一起的情况我读书的时候看到这么一句话：One day I droped in on an old friend.（有一天我去拜访我的一个老友）,请问为什么in和on可以放在一起?droped 和 in 放在一起是词组我知 我十二岁 I twelve year old 为什么书上是I am twelve我十二岁 I twelve year old 为什么书上是I am twelve year old 为什么加am(是) year old,year-old,years old,years-old的区别 how old is the old woman i think she isA.70-year-old B.70 yearsC.70 year old D 70 years old 说下为什么 is a （）girl.答案是13-year-old为什么eight-year-old不对 表示年龄的英文如果说年龄.是 two hundred years old 还是 two hundred year old 呢.为什么. I think ____should not drive anywhereA.sixteen-year-old B.sixteen-years-old C.sixteen-year-olds为什么 an 8-year-old 为什么加an而不是a,是不是8是元音开头的? I am born ten year old.的问句是什么 your ten year-old brother is the only boy among你的十岁的弟弟是我们当中唯一的男孩这里的among是介词,为什么要放在最后呢? 英语这样的复合词怎么用?4-year old还是4-year- old?4 years old还是4 years' old为什么 20 minutes' ride而不是20 minutes ride?什么时候要加'S或者'?横线究竟是一条还是两条? I am eleven years old ths year.的同义句__ __ __eleven this year. 英语选择题（见问题补充说明）I don't think_______can undestand all the things.A.a 10-year-old boy B.an 10-year-old boy (答案是B,为什么呀） Tell me where do i find someone like you girl的问题怎么会出现you和girl放在一起请解释一下是同位语为什么没有逗号 是a eight-year-old 还是an eight-year-old year-old与years old的区别 单选I think___shouldnot be allowed to drive.A.sixteen-year-old B.sixteen-year-olds 为什么选B,