they asked who the man was that was waliking the dog.为什么有两个was,为什么有that

they asked who the man was that was waliking the dog.为什么有两个was,为什么有that

他们问正向狗走去的那个男人是谁.
这是一个复合从句：宾语从句中套定语从句.
第一个was是宾语从句中的系动词,第二个was是定语从句的进行时was walking.
that.是the man 的定语,因为关系代词that 在定语从句中做主语,所以是替代了who.