he was seen to hang out.为什么要to

He was nowhere to be seen.为什么要用不定式 he was seen to go out by me He was seen to go into the room 这里为什么SEEN后加TO 1He was seen（ ）out A.go B.to go c.went D.goes he was nowhere to be seen. He was seen to cross the street. He came out to see what was the matter?为什么不能写成He came out to It's exciting to hang out with friends on sundays为什么用to hang (seen)to entered the room ,he was asked to the policeman.为什么 he was seen to drink.这个句子对吗? he was seen drinking.呢? Nancy is often seen_______(hang) out on weekends.to hang 1.-Henry doesn't seen to be what he was.