And that's when they're used in relative clauses to introduce adjective clauses.

那就是形容词性的定语从句里面。

This one, however, we're adding more information in this relative clause here.

然而，我这个关系从句中添加了更多的信息。

We use them in relative clauses too.

我关系从句中使它。

This is where we come to adjective clauses, also called relative clauses.

这就是我要讲的形容词从句，叫关系从句。

When the relative pronoun represents the object of the relative clause, such as in sentences b) and d) , it can be left out.

当关系代词指定了定语从句中的宾语，比如第二句和第四句，它就可以被省略。

But, 'that' can only be used in what we call identifying relative clauses and those are clauses where you need the information to understand what you're talking about.

但是，That只我所谓的身份辨识分句中，而这种分句提供信息来帮助别人理解你正谈论的内容。

The " he can't refuse" part of the sentence is a relative clause. It is modifying, or changing the meaning, of the noun " an offer."

句中 “he can't refuse” 是一个关系从句。它对名词 “an offer” 进行修饰或改变其含义。

Another common structure is relative clauses, using relative pronouns like who, which or what to link two clauses.

另一个常见的结构是关系从句，使关系代词，如“who”、“what”或“what”来连接两个从句。

There is the clauses, so a mixture of subordinate dependent or non dependent clauses, relative clauses.

有从句，由从属从句或非从句、关系从句混合而成。

We discussed relative clauses in an earlier Everyday Grammar story.

我之前的每日语法已讨论了关系从句。

A relative pronoun is used to connect a relative clause to the rest of a sentence.

关系代词来连接一个关系从句和句子的其余部分。

The relative clauses here all begin with 'who' or 'whose'.

这里的关系从句都以 who 或 whose 开头。

Now, 'that' is less formal, and it can be used for both people and things in some relative clauses.

That的法稍微有点不正式。一些关系分句中，它可以同时来修饰人和物。

Now these words are exactly what we're going to talk about today, 'which' or 'that' in relative clauses.

这两个单词就是我今天要讨论的内容啦，关系从句中的‘which’或‘that’。

The last relative pronoun " what" can also be used in relative clauses, but it is different.

最后一个关系代词 “what” 可以定语从句中，但是它比较特别。

So for example, I'm living in London which is a beautiful city. Relative clause, two clauses.

I'm living in London which is a beautiful city.关系从句，两个从句。

Defining relative clauses such as these specify which noun we are talking about.

像这些句子就是限定性定语从句了，限定了我所讨论的名词是哪个。

Relative clause, adjective clause, what are we talking about? That sounds confusing!

关系从句，形容词从句，我说什么呢？完全听不懂啊！

Relative clauses are another useful topic if you want to improve your sentence grammar.

如果你想提高你的句子语法水平的话，关系从句是另一个非常有的话题。

Thirdly, don't use relative clauses, with who, which, that, where, etc. , unless it's really necessary.

第三，不要 who、which、where 等引导关系从句，除非真的很有必要。