为什么write down something不是按照代词放write down中间的规律来的?

write it down it 为什么在down前 为什么write down something不是按照代词放write down中间的规律来的? write down the number on为什么要用on? write down the number on为什么要用on? write down on the blackboard“写在黑板上”,其中down可以省略吗?说成write on the blackboard?为什么 为什么可以write it down ,有时不可以write down it?类似的句子的用法请说一下. Write down these 英语造句:write down write it down write it down 用write down 造句 write down theopposite words 用write down造句 write it down. write down 和write on的区别 inventory write-down和inventory write-off 英语：Does he need to write down his name ? 为什么用to,求英语：Does he need to write down his name ?为什么用to,求解释 write it down和write them down的区别