判断改错：
( ) This is the mountain village where I visited last year.
( ) This is the mountain village which I visited last year.
( ) I will never forget the days when I spent in the countryside.
( ) I'll never forget the days which I spent in the countryside.
方法二： 准确判断先行词在定语从句中的成分(主、谓、宾、定、状)，也能正确选择出关系代词/
关系副词。
1)This is the museum ___ you visited a few days age
A. where B. that C. on which D. the one
2)This is the museum ____ the exhibition was held.
A. where B. that C. on which D. the one
关系词的选择依据在从句中所做的成分，先行词在从句中做主、定、宾语时，选择关系代词(who, whom,that, which, whose); 先行词在从句中做状语时，应选择关系副词 (where 地点状语，when 时间状语，why 原因状语)。
5.限定性从句和非限定性从句 外语教@育网www.exam8.com
1)定语从句有限制性和非限制性两种。限制性定语从句是先行词不可缺少的部分，去掉它主句意思往往不明确;非限制性定语从句是先行词的附加说明，去掉了也不会影响主句的意思，它与主句之间通常用逗号分开。例如：
Her sister who is a nurse stands there.(限制性)
Her sister, who is a nurse, stands there. (非限制性)
All the Greeks who are philosophers are very clever. (限制性)
All the Greeks, who are philosophers, are very clever. (非限制性)
2) 非限制性定语从句还能将整个主句作为先行词, 对其进行修饰, 这时从句谓语动词要用第三人称单数。例如：The traffic of Beijing is quite bad, which is known to everyone.
6.定语从句的省略
(1) 关系代词充当从句宾语
我们前面说到连接词在定语从句中充当一个成分，有可能是主语、有可能是宾语，我相信大家肯定还记得，这里我们要告诉大家，当这些连接词充当的是宾语时，可以省略。例如：
1. The book (that/which) we bought last year is now very popular.
2. We can see the boys (who/whom/that) the teacher is talking with are quite happy.
上述第一句的book是先行词，作后面的定语从句中bought的宾语，故引导词that/which可以省略，第二句的先行词students作with的宾语，故引导词who/that/whom也都可以省略，
(2) 关系代词充当从句主语
当关系代词充当从句主语时，也可以省略，但是省略后的从句要发生形式的变化，原从句若为主动语态，后面的动词结构要变成分词ing形式，原从句若为被动语态，后面的动词结构直接为过去动词结构。这种结构在英语语法中称为分词作定语。
The novel which was given by the professor mainly discusses the development of Chinese economy.
The novel given by the professor mainly discusses the development of Chinese economy.
The novel which mainly discusses the development of Chinese economy was given by the professor.
The novel mainly discussing the development of Chinese economy was given by the professor.
SP: (1) why的先行词reason或可用that 指代的名词也是定语从句的原因状语时，例如：
1. That is the reason (for which/why) you dislike it.
2. I wonder the reason (why/for which) he changed his mind.
(2) 表示方式的先行词way，其后的关系代词可用that，也可省略，例如：
1. Everyone does not like the way (that) he talks.
2. Do you know the way (that) the teacher treated his students.