1. 形式上，非限制性定语从句往往用逗号隔开。

1. This is the way (that)　 /in which　 I do such things.

比较: Please do the experiment in the way (that/which)I have shown you.

Ⅳ. 限制性定语从句与非限制性定语从句的区别：

2. I don't believe the reason (that/which) he gave me. (作宾语)

Have you asked him the reason that may explain his success? (作主语)

Ex.) He was late .That's because he got up late.

　　 .He got up late. That's why he was late.(表语从句)

　　　　　　　　　　　　　　　 (the reason) why/for which he was late. (定语从句)

当先行词为way时，定语从句常用that, in which,或how引导，that常可以省略。

way后的定语从句 的引导词不用时较多。但如果关系词在句中作主语或宾语

时，则用which或that 引导。如:

1.　 The reason why / for which / (that) he didn't attend the meeting was that he was ill.(作状语)

2. This is the park which/that they visited last year. (作宾语)

Not having been there before, he simply had no idea about the place, which everyone says is worth visiting.

　Why 指原因，在定语从句中作原因状语。先行词为reason 时，可用for which指代；当关系词在从句中作主语或宾语时，则用which或that 引导。如：

2. I live in the room where /in which he used to live.

注意：先行词是"地点名词"，定语从句可用where引导，还可用which或that引导，which/that 在从句中作主语或宾语。

比较: 1. This is the factory where /in which he worked last year. (作状语)

The treatment will continue until the patient reaches the point where he can walk correctly and safely.

I think you have got to the point where a change is needed, or you would fail.

Government reports, legal papers and most business letters are the main situations where English is used.

He's got himself into a dangerous situation where he's likely to lose control of the plane.

The small mountain village where we spent our holiday last month lies in what /the place which is now part of Hubei.

1. This is the place where I was born.

3. I shall never forget the day when Shen Zhou Ⅴ was launched, which has a great effect on my life.

There are occasions when joking is not permissible.

Where 指地点，在定语从句中作地点状语。其先行词是表示地点的名词，如：place, school, factory, room, etc. 如:

2. I still remember the days which/that we spent together. (作宾语)

Next winter which/that you'll spend in Harbin, I'm sure, will be exciting.

2. We will put off the picnic until next week, when the weather would be better.

注意：先行词为"时间名词"，可用when引导定语从句，when在定语从句中作状语；还可以用which或that 引导，which或that在从句中作主语或宾语。

比较: 1.I still remember the day when /on which my brother joined the army.(作状语)

Next month, when you will be in your hometown, is just around the corner.