定語可以由形容詞、代詞、數詞、名詞、分詞、不定式、介詞短語等來擔任，修飾名詞。(以分詞、介詞短語爲例)
例： The girl behind the tree is Kate.
The man driving too fast was a drunk.
定語從句
在英語中，修飾名詞或代詞的句子叫定語從句。
例： The girl who is behind the tree is Kate.
The man who was driving too fast was a drunk.
關係詞判 斷 步 驟 :
首先，要辨別出先行詞。 如果先行詞是指人,關係詞可能就用
who, that, whom ,whose。如果先行詞指物,關係詞可能用which或that
h指物，做主語或賓語 (作賓語可省 略, 指人,做主語或賓語 (作賓語可省略)
指人,作賓語 (作賓語可省略,
4.關係代詞that 指人/物，做主語或賓語 (作賓語可省略)
有些情況下只用關係詞that,而不宜用which
1.,只能用that引導從句.
This is the most interesting story ( that )I have ever heard.
The first meeting ( that) we will take part in will be held in the afternoon.
2.先行詞是all, something, nothing, anything不定代詞時,只能用that.
Here is something ( that) I will tell you.
Not all that glitters is gold.
3.先行詞既有人也有物時,只能用that引出從句
I can remember well the persons and some pictures(that) I see.
4.先行詞是one of, the one, 或用little ,few, no, all ,any 作修飾，用that
Is it the one that you want ?
We haven’t got much that we can offer you.
5.當主句已有疑問詞 who或which時，關係詞用that
Which is the bike that you lost?
Who is the woman that was praised at the meeting?
從例句中看出，who、that在許多情況下可以通用，但有時宜用用who,而不用that
1.先行詞是one(s) ,anyone, someone, those時，關係詞使用who
Those who want to go to the Great Wall sign up here.
One who has nothing to fear oneself dares to tell the truth.
2.在there be 句型中，先行詞指人,關係詞用who
There is an old man who wants to see you.
There are many young men who are against him.
關係副詞是用來引導定語從句的，它和關係代詞一樣，具有3種作用。
在從句中代替先行詞。在句中作狀語 連接作用，把兩個句子連接成爲一個帶有定語從句的複合句 關係副詞有三種：
where:在從句中作地點狀語,指代地點. ( on in/at…which)=that when: 在從句中作時間狀語,指代時間。(on / in…which)=that why: 在從句中作原因狀語,指代原因 =that
關係副詞的.用法：
e 的用法：(先行詞應是地點名詞)
The hotel wasn’t clean. + We stayed at the hotel
=The hotel where we stayed wasn’t clean
=The hotel at which we stayed wasn’t clean.
=The hotel which we stayed at wasn’t clean
=The hotel 關係詞略we stayed at wasn’t clean
的用法： (先行詞應是表示時間的名詞)
I’ll never forget the day. + I joined the League on that day. I’ll never forget the day that I joined the League.(口語) I’ll never forget the day on which I joined the League . I’ll never forget the day when I joined the League.
的用法： ( 表示原因的名詞) s to invite you to a party
