定语从句相关问题求教I have two grammars,___are of great use.答案是both of

I have two grammars,___are of great use.答案是both of which
以上是个非限制性定语从句,WHICH 指代前面的TWO GRAMMARS,BOHT OF WHICH=BOTH OF TWO GRAMMARS 意思,两本语法书都很大用处
In our factory there are 2000 workers,two thirds of ___are women.答案是whom不是which
以上是个非限制性定语从句：指代,部分与整体之间关系,先行词是人,因此引导非限制性定语从句关系代词应该是WHOM ,TWO THIRDS OF WHOM ,=TWO THIRDS OF 2000 WORKERS ,2000工人中2/3是女人,
I have bought 2 ballpens,___writes well.答案是neither of which.
以上是个非限制性定语从句,WHICH 指代前面表示物的2 BALLPENS 先行词,NEITHER OF WHICH= NEITHER OF 2 BALLPENS,2支圆珠笔种没有一支是很好写的.
Is ___ some German friends visited last week?答案是this the school而不是this school where
这个句子是正确的 Is this the school some German friends visited last week
先行词=THE SCHOOL ,关系代词THAT /WHICH 指代THE SCHOOL ,在定语从句中充当宾语从句,所以被省略了,
This is the hotel ___last months.答案是where they stayed
先行词=THE HOTLE ,引导定语从句关系副词=WHERE,WHERE=IN WHICH ,从句缺状语成分,因此需要用关系副词引导定语从句
完整句子：This is the hotel where they stayed last month

1. which指代物，who指代人，第一题的grammar“语法书”是物，第二题的worker工人是人。

2. Is ___ some German friends visited last week? 你把答案填进去再转化成陈述句，填this the school就变成this is the school some German friends visi...

区别在于第一、三题从句中主语是物，第二题从句中主语是人‘

Is this the school some German friends visited last week?这是主句是Is this the school 从句which some German friends visited last week，which省略了
visit是及物动词，从句中缺宾语，只能用...