英语单词see后除了跟动名词形式外,还可以跟动词原形还是动词不定式

1.see sb doing 看到某人正在做某事
I saw him playing basket on the playground.
2.see sb do 强调动作的全过程(要注意这里的do 是省略to的不定式)
I saw him go into that room
如果变为被动to不省略
He was seen to go into that room
3.see sb done 表宾语和动词之间是被动的关系。
I saw him tied to a tree yesterday.
我昨天看见他被绑在一棵树上了。

此类词还有:
see,watch,look at,observe
hear, listen to.
feel

原形 感官动词．相当于省TO 的不定式 象这样的感官动词还很多hear,feel,watch ......

see sb doing sth
或者see sb do sth都行,但意思不同,前面是看到某人正在做某事4,强调偶然的一次,后者则是经常看到某人做某事