which一詞在科技英語中應用極為廣泛,是科技英語中使用比較頻繁的語法修飾成分,它的使用使句子變得更長更復雜。下面小編就來介紹下which修飾句子的用法。

　　只能使用which的情況:

　　1. 在“介詞+關系代詞”結構中，關系代詞必須用which。如：

　　The house in which we live is very large. 我們住的房子非常大。 This is the reference book of which the teacher is speaking. 這就是老師正在談及的那本參考書。

　　注意： 如果介詞不放在修飾事物的限定性定語從句的句首， which就可換為that， 如：

　　This is the question which/that we’ve had so much discussion about. =This is the question about which we’ve had so much discussion. 這就是我們已經多次討論過的問題。

　　2. 先行詞為“those+表事物的復數名詞”時， 關系代詞通常只用which而不用that。如：

　　you should grasp well those skills which may be used in the future work. 3.如果先行詞是that,關系代詞應用 which。 I have that which you gave me.

　　4.一個句子中如有兩個定語從句,第一個定語從句用了關系代詞that,第二個從句中的關系代詞宜用which，但在平行結構中,應重復同一個關系代詞，如： This is the book that you bought which you have lost.

　　I have a house which is located on the hillside, which faces the south. 5.如先行詞和定語從句之間被其它較長的成分分隔,常用which?

　　Larry told her the story of the young airman which I narrated at the beginning of this book. (先行詞為story)

　　特殊情況：當先行詞是表示原因或方式的名詞時，可以用that引導定語從句，相當于介詞+which，that可以省略。

　　如： She likes the child for the very reason that (=for which) she loves his father. 她喜歡那個孩子因為她愛著孩子的父親。

　　He didn’t like the way that (=in which = \) she speaks to his mother. 他不喜歡她對他的母親那樣說話。

　　that和which在從句里都可以做賓語和主語，做賓語時可以省略。(The place which\that\不填Ivisited yesterday was boring.)在定語從句中,關系代詞在限制性定語從句中作賓語可以省略,不管是that，which，還是whom。但是which能引導非限制性定語從句，that則不行。

　　只能用that的幾種情況：

　　1. 當先行詞為all, much, little, none及由any, every, some, no所構成的復合不定代詞時。

　　如：We should do all that is useful to the people. 我們應該做一切有益于人民的事情。

　　Please tell me anything that you know about the matter. 有關此事，凡是你所知道的請告訴我。

　　2. 當先行詞被any, few, little, no, all, much, some等詞修飾時。 如：You can take any seat that is free. 任何空著的座位你都可以坐。 There is little work that is fit for you. 幾乎沒有適合你的工作。 3. 當先行詞為序數詞或被序數詞所修飾時。

　　如：When people talk about the cities of China, the first that comes to my mind is Beijing. 人們談論起中國的城市的時候，我首先想到的是北京。

　　This is the fourth film that has been shown in our school this term. 這是我們校本學期放映的第四部電影。

　　4. 當先行詞為形容詞最高級或被形容詞最高級修飾時(the best , the most等) 如：The best that I could do was to apologize. 我唯一能做的就是賠禮道歉了。 This is the most interesting story book that I have ever read. 這是我讀過的一本最有趣的故事書。

　　5. 當先行詞被the very, the only, the last, the just, the same等修飾時。 如： This is the very book that I’m looking for. 這正是我在找的書。

　　The only thing that we could do was to wait. 我們唯一能做的事就是等待。 注意：先行詞被the same修飾時，關系代詞也可用as。如：I need the same book that / as you have. 我需要有你一樣的書。 6. 當先行詞既包含人又包含物時。

　　如： They are talking of the heroines and their deeds that interest them. 他們正在談論他們感興趣的女英雄及她們的事跡。

　　7. 當先行詞是疑問代詞who，which，what或主句以這些詞開頭時。

　　如：Who that has ever worked together with him doesn’t admire him? 曾經和他一起工作過的誰不欽佩他?

　　Which is the star that is nearer to the earth? 哪個是離地球比較近的星星? 8. 當先行詞為主句表語或關系代詞為從句表語時。

　　如：That’s a good book that will help you a lot. 那是本對你很有幫助的書。 Our school is no longer the place that it used to be. 我們的學?，F在已不是過去的那個樣子了。

　　9. 先行詞為time時，當time表示次數，引導詞用that, 可省略。 當表示時間，可用that或when引導，都可省略。 如：I do remember the first time(that) I had ever heard the sweetest voice in the world.我很清楚地記得當我第一次聽到世界上最美的聲音的時候。 I did't remember the exact time (when/that) I arrived in Shanghai last month. 我不記得上個月到達上海的確切時間了。

　　10.在固定結構the same...that...; so...that...; such...that...以及it is/was...that...的強調句型中,須用that。如： This is the same museum that you once visited.