1.that既可代表事物也可代表人,which代表事物；它們在從句中作主語或賓語,that在從句中作賓語時?？墒÷躁P(guān)系詞,which在從句中作賓語則不能省略.而且,如果which在從句中作“不及物動詞＋介詞”的介詞的賓語,注意介詞不要丟掉,而且介詞總是放在關(guān)系代詞which的前邊,但有的則放在它原來的位置
2.which作賓語時,根據(jù)先行詞與定語從句之間的語義關(guān)系,先行詞與which之間的介詞不能丟
3.代表物時多用which,但在帶有下列詞的句子中用that而不用which,這些詞包括當(dāng)先行詞是anything,everything,nothing ,few,all,none,little,some等代詞時,或者是由every,any,all,some,no,little,few,much等修飾時等,這時的that常被省略
4.who和whom引導(dǎo)的從句用來修飾人,分別作從句中的主語和賓語,whom作賓語時,要注意它可以作動詞的賓語也可以作介詞的賓語
5.where是關(guān)系副詞,用來表示地點的定語從句
6.when引導(dǎo)定語從句表示時間〔注〕值得一提的是,表示時間“time"一詞的定語從句只用when引導(dǎo),有時不用任何關(guān)系代詞,當(dāng)然也不用that引導(dǎo)
By the time you arrive in London,we will have stayed there for two weeks.I still remember the first time I met her.Each time he goes to business trip,he brings a lot of living necessities,such as towers,soap,toothbrush etc.
7.whose是關(guān)系代詞,修飾名詞作定語,相當(dāng)于所修飾成分的前置所有格.它引導(dǎo)的從句可以修飾人和物,當(dāng)它引導(dǎo)的從句修飾物體時,可以與 of which 調(diào)換,表達(dá)的意思一樣.
8.當(dāng)從句的邏輯主語是some,any,no,somebody,anybody,nobody,something,anything,everything或nothing時,常用there is來引導(dǎo)
There is somebody here who wants to speak to you.這里有人要和你說話.
編輯本段（二）非限定性定語從句
非限定性定語從句的作用是對所修飾的成分作進(jìn)一步說明,通常是引導(dǎo)詞和先行詞之間用逗號隔開,將從句拿掉后其他部分仍可成立
1.which引導(dǎo)的非限定性定語從句來說明前面整個句子的情況或主句的某一部分
2.當(dāng)先行詞是專有名詞或物主代詞和指示代詞所修飾時,其后的定語從句通常是非限制性的,例如：
Charles Smith,who was my former teacher,retired last year.查理·史密斯去年退休了,他曾經(jīng)是我的老師.
My house,which I bought last year,has got a lovely garden.我去年買的的那幢房子帶著個漂亮的花園.
This novel,which I have read three times,is very touching.這本小說很動人,我已經(jīng)讀了三遍.
3.非限制性定語從句還能將整個主句作為先行詞,對其進(jìn)行修飾,這時從句謂語動詞要用第三人稱單數(shù),例如：
He seems not to have grasped what I meant,which greatly upsets me.他似乎沒抓住我的意思,這使我心煩.
Liquid water changes to vapor,which is called evaporation.液態(tài)水變?yōu)檎羝?這就叫做蒸發(fā).
4.有時as也可用作關(guān)系代詞
5.在非限定性定語從句中,不能用關(guān)系副詞why和關(guān)系代詞that,而用who,whom代表人,用which代表事物.；
（十）關(guān)系代詞that 的用法
(1)不用that的情況
(a) 在引導(dǎo)非限定性定語從句時.
(錯)The tree,that is four hundred years old,Is very famous here.
(b) 介詞后不能用.
We depend on the land from which we get our food.
We depend on the land that/which we get our food from.
(2) 只能用that作為定語從句的關(guān)系代詞的情況
(a) 在there be 句型中,只用that,不用which.
(b) 在不定代詞,如：anything,nothing,the one,all,much,few,any,little等作先行詞時,只用that,不用which.
(c) 先行詞有the only,the very,the same,the last,just修飾時,只用that.
(d) 先行詞為序數(shù)詞、數(shù)詞、形容詞最高級時,只用that..
(e) 先行詞既有人,又有物時.
(f) 先行詞指物,在主句中作表語時．
(g) 為了避免重復(fù)．
(h)先行詞是the way時
舉例：
Is this the book that you borrowed in the library?
這是你在圖書館借的那本書嗎?
Who that break the window should be punished．
誰打碎了窗戶都要受到懲罰．
All that is needed is a supply of oil.
所需的只是供油問題.
Finally,the thief handed everything that he had stolen to the police.
那賊最終把偷的全部東西交給了警察.