little Tom was seen-------为什么seen后为crying而不是to cry?

little Tom was seen-------为什么seen后为crying而不是to cry? He was seen to go into the room 这里为什么SEEN后加TO 为什么是remain to be seen 而不是remain to see He was nowhere to be seen.为什么要用不定式 When I was little ,I was embarrassed to be seen with my fath A little girl was seen to fall into the lake by a PLA man.he when passing me he pretended _me 为什么要填not to have seen 而不是no he was nowhere to be seen. He was seen to cross the street. Tom was seen playing on the playground是什么? 英语中Ifound a little boy crying in the room 中crying为什么不是is cry They was seen to come into the room by her还是Thry was seen to