YOU SAID:

one day i see an old man walking on the street and fall

INTO JAPANESE

ある日、老人が通りを歩いて転ぶのを見る

BACK INTO ENGLISH

One day I see an old man walking down the street

INTO JAPANESE

ある日、老人が通りを歩いているのを見る

BACK INTO ENGLISH

One day I see an old man walking down the street