n.过路人,使通过者
He was tripped up by a passer-by.
他被一个路人绊倒了。
The purse was picked up by a passer.
钱包被一个过路人捡到了.
A passer - by called the emergency services ( = the ambulance / fire / police services ).
一名 路人 拨打了紧急救险服务电话.