动词leave在做动词“离开”意思讲的时候，既是及物动词，也是不及物动词，如：
I left.
I left the place.
都是完整的句子。那这里就有一个问题是，怎么分辨后一个地址名词是宾语呢？还是状语呢？
有这么一道题：
What did he see when he came back to the spot _____ he left？
A. that B. which C. where
假如这里将先行词理解为从句宾语，那样that和which仿佛都可以；假如这里将先行词理解为从句状语，仿佛where也可以。所以感觉到非常疑惑，还请老师解惑！
我猜本题的参考答案是C where，并且我也觉得应该选C，而不是A或B。
本句的重要不是定语从句修饰地址名词时怎么样选择关系词，而是动词leave表示离开某地或某处，在前面已经提及该地或该处的状况下，应该用代词还是副词指代该地址或处所的问题。
比如，“他来到市场, 买了些东西，然后离开了。”这句话用英语表达时假如用leave作谓语，是不可以重复名词市场的。要么leave用作不及物动词，要么用the place作宾语，要么用副词there作宾语，但较少用人称代词或指示代词指代该地址。
He came to the market, bought something and left a few minutes later.
He came to the market, bought something and left there a few minutes later.
He came to the market, bought something and left it a few minutes later.
大家读上面三个句子，会感觉前两句leave用作不及物动词或后接there作宾语读起来非常自然，而用it指代market则有的不自然。
动词leave作离开解时，是可将来接副词here，there，somewhere作宾语的，特别是口语中，并且后接人称代词it指代地址更容易见到。
关系词引导定语从句，其实就是关系词取代了人称代词、指示代词和指示副词。
既然地址副词可以作leave的宾语，关系副词引导定语从句时就能作leave的宾语。it指代地址，作leave的宾语不及there自然，所以where引导定语从句并在从句中作leave的宾语，就比关系代词which或that（取代it）自然。
单选题是选择最好答案，不是唯一正确答案，故where为最好答案，优于用which或that。
关于leave后接地址副词作宾语证明：
1 COCA例句
When heleftthere, hed asked me to come with him to the city.
Thats been circulating every year since Ileftthere.
Reports said they initially went into the sheriffs office but later witnesses reported theyleftthereand drove away.
Ilefttherefor an hour and a half.
...but everybody understood we had to get a usable document by the time welefttherea week after the July Fourth weekend.
...and there had been a few other things since Idleftthere, ...
But hopefully theylefttheresaying, I love Coach Avalos.
Youlefttherecrying, did you say?
2 BNC例句
Weleftthere, we left about half five, six in the morning didnt we?
We should of just got in the car andleftthereand then, parked
I was two when weleftthere.
But sheleftthereand got another job in.
Well when Ileftthere, and joined the army, I was getting twenty seven shillings a week.
Oh I cried when Ileftthere, I really did, it upset me.
...and I think I was about fifteen when Ileftthere.
3《朗文》注解词义时的用语
set off：（especially British English）to leave somewhere and begin ajourney
go：（especially spoken）to leave somewhere
