一、选准关系代词和关系副词

在定语从句中，关系代词或关系副词都代替先行词在从句中充当一定的成分，如果该从句中缺少主语、表语、宾语或定语，就要用关系代词来连接从句；如果从句中缺少状语，就得用关系副词来连接从句。例如：

(1)I still remember the days which / that we spent together.

(2)I still remember the days when we worked together.

二、了解仅用that 引导限制性定语从句的几种情况

that 在限制性定语从句中既可指人又可指事或物。在下列情况下，只能用that 来引导定语从句：

1. 先行词是all , much, few, little, everything, anything, nothing 等不定代词时。例如：

Is there anything that you want to buy?

2. 先行词被all, few, little, much, every, some, no等词修饰或被the only, the very, the same, the last 等限定词修饰时。例如：

These are all the pictures that I have seen.

This is the very dictionary that is of great help.

3. 先行词既指人又指物时。例如：

My father and his teacher talked a lot about the things and the persons that they could remember.

4. 关系代词在定语从句中作表语时。例如：

Our school is not the one that it used to be.

5. 先行词被形容词最高级或序数词修饰时。例如：

This is the best English film that I have ever seen.

The first English novel that I read was A Tale of Two Cities.

6. 主句是who 或which 引导的特殊问句时。例如：

Who is the girl that is standing under the tree?

Which is the machine that we used last Sunday?