see sb 怎么不是doing或done

see sb do
非谓语形式do 基本上是不持续的动词
I saw her come to school yesterday .
see sb doing
doing 一般是持续动词
I saw her standing in front of cinema
see sb done
给你一个例子
What surprised me most was to see some of the village people _____on the benches at the end of the room.
A.seating B.seated C.seat D.to be seated
答：B对,为see sb.done结构,seated为过去分词作宾补,表状态＝sitting,seat为及物动词,后面没宾语时要用被动式seated,意“坐着”,see后面不接带to的不定式作宾补,故D不对,其to be应省去.
see sb do 就是看到一个时间点上的事情
see sb doing 看到的是一段时间的,你记住,动词一定是持续的
持续动词就是动作能保持一定时间的动词,比如说等待啦 wait 站拉 stand 睡觉拉 sleep 唱歌啦sing等