英语翻译I can think of many cases （where） students obviously kne

最浅显易懂的解释：
where = in which 你完全可以把where 替换成in which
同样类似的有
the conditions where = the conditions on which
the circumstance where = the circumstance under which
这些都是可以替换的,完全相等的.
不要去记什么“抽象地点名词”,越这样想越懵,就简简单单的分析一下从句的结构就很明了了.
【从语法角度看】
分析句子：
I can think of many cases 【where students obviously knew a lot of English words and expressious but couldn't write a good essay】.
(1)显然cases后面是定语从句,cases是先行词,先不看where,看看从句说的是什么.
(2)我们知道先行词在从句中必须要做一个成分,否则的话,定语从句和先行词的关系就不能被描述出来.定语从句中,最关键的一点就是从句和先行词的关系,这直接决定了选择哪一个关系代词.基本上所有的题目都是考查这一点的.
比如,做主语的时候必须用 who/which,或that,非限定性修饰的时候不能用that,强调最高级或唯一的时候只能用that,做宾语的时候可以省略关系代词,等等.
(3)那么现在看这个从句中,case做了什么成分：
【students obviously knew a lot of English words and expressious but couldn't write a good essay】students knew...but couldn't...这是一个非常完整的句子,什么都不缺,找不到任何CASE的踪迹.那CASE与从句到底是什么关系?
发现从句就是描述这个case的,如果硬要把case放在从句里,我们可以这样说：
【in these cases,students obviously knew a lot of English words and expressious but couldn't write a good essay】翻译为：【我可以想出来好多情形,这些情形说的是：学生背了很多单词和短语但是写不出好文章.】这正是我们要的意思.
(4)所以,像我刚才所说那样,标准的定语从句就是这样的：
I can think of many cases 【in which】 students obviously knew a lot of English words and expressious but couldn't write a good essay.(这个是多么合情合理啊.)
而为什么in which 可以换成where?因为in 就是一个表示地点的介词啊,介词加以一个名词,字面上的意思不就是表示地点吗,因为实在不知道怎么才能很贴切的描述这种“感觉”,所以那些人就干脆新编一个词,叫“抽象地点名词”,实际上更不好理解了.
(5)事实上,这种情况很好判断：当表示“情况”“假设”“条件”这类意义的词语作为先行词的时候,其实都可以接where从句,后面用一句完整的话来描述所说情况.
而且,当可以用in which,on which .这种形状的方位介词+关系代词的结构式,一般这个结构都可以换为where.
(6)另外一些例子
如果你可以理
Set the time 【at which】 this certificate will expire (the validity period).
这里的【at which】就是【when】的话,那么其他情况都很好理解了
以下几种情况与这个情况是一样的：
the place 【in which】 the goods are to be regarded
in the place【 to which】 you are pleased to go
Receiving station is a place 【where】 messages are received
a place 【from which】 the messages are sent is called transmitting .
there are special cases【 in which】 it is impossible for the Party member concerned to attend in person the meeting 【at which】 such a decision is to be made by a Party organization.Such cases,however,should be regarded as an exception.当然,在某些特殊情形下面,党组织作决定的时候,不可能让党员亲自参加,但是,这应该看作一种例外.
For cases【 in which】 there is no such formality,including most rulemaking cases,additional principles must be examined.
对于那些没有此种形式的案件,包括大多数制定规则的案件,则必须检查其他的原则.
set of conditions 【under which】 work is performed
conditions【 on which】 such land may be sold or otherwise disposed of.
"In respect of clean collections,partial payments may be accepted if and to the extent 【to which】 and on the conditions 【on which】 partial payments are authorised by the law in force in the place of payment."
光票托收时,只有在付款地现行法律准许部分付款的条件和限度内,才能接受部分付款.
以上所有【这部分】都可以换成where.

我能想到很多这种情况：学生明显地知道很多单词和短语，却写不出一篇好的文章。先行词cases在从句中不作成分，因而为状语。又cases表“情况、情形”一般为where

因为这个定语从句的主干成分完整，且先行词为抽象的地点名词，所以用关系副词where来引导这个定语从句