是“I saw an old man fall down”还是“I saw an old man fell down”

是“I saw an old man fall down”还是“I saw an old man fell down” I saw an old man k_____ down by a car yesterday. .I,around,an,man,when,was,down,fall,walking,the,saw,station, What would you do if an old man fell down 问大家一个关于英语语法的问题..老师写了一个句子（I saw an old man knocked down by a “I saw an old lady knock down by a motorbike while she was w I saw an old man _____(lie) on the around when I walked past I saw an old man ____(lie)on the ground when I walked past. I saw an old man ___ in the entrance hall when I came to the run an old man down,翻译 When I saw the old man __loff his bike,Iran to hin t once an I saw an old man and the dog________（正在街上散步的） 填什么?