定語 從句由關係詞（關係代詞、關係副詞）引導，關係代詞、關係副詞位於定語從句句首。
定語從句例子先行詞
Chinese knots ,which I made by myself with red silk thread and other material, look really beautiful in the shape of diamond.（2013年廣西卷）
2. I will organize some campus activities, like “English Evening”, a platform where students can show their English（2013年天津卷）
3.I read the announcement of the summer camp that you have posted on the Internet and I am interested in it. (2012全國卷)
4. In the English corner, I meet many friends, who share the same interest with me. (2012·全國卷Ⅱ)
5. My physics teacher is my role model, whose influence on me had a lot to do with my decision.（2012安徽卷）
6. To avoid such conflicts, we should be kind to one another, which is essential to enjoy a harmonious life.（2012江蘇）
7. As we know, books are the source of knowledge. (2012·湖北)
8. Dear friends , please actively take part in after-class activities , which will not only make your school life colorful , but also improve your learning.（2011四川卷）
9. I have taken with me the two books (that) you asked me to return to the City Library. (2009全國I)
reason why we have to grow trees is that they supply us fresh air.
11. I always miss the days when we were on the summer camp last year.
12. It's time to recall those beautiful days we spend together.（2007年湖南卷）
定語從句特定選擇
關係詞
1、只用that不用which
1）當先行詞是序數詞或被序數詞、最高階，關係詞用that。
2）當先行詞既有人又有物時，用that。
3）當先行詞帶有the only,the very,the same,the last,the one等詞時，用that。
4）當主句中有who或which時，為避免重複用that。
5）當先行詞為something，anything，nothing，none，no，little，much，all等不定代詞時用that。
2、只用who不用that
1）如果先行詞是those,they,all,persons,people,he,anyone,one時用who
2）當先行詞指人並含有較長的後置定語從句或在被分割的定語從句中時。
3、只用which不用that
1）當主句先行詞後有介詞時，用which。例：This is the one of which I'm speaking。
2）非限定性定語從句，用which。
3) 描述句中一般用which。例：Beijing，which was China's capital for more than 800years。
4）those +複數名詞之後，多用which .例：Shopkeeper want to keep a number of those goods which sell best。
5）先行詞本身是that時，用which。
定語從句誤區提醒
1）當表示時間或地點的名詞作先行詞時，要判斷出它們在從句中作狀語還是主語或賓語。作狀語時用關係副詞，反之用關係代詞。
典型例題：I can never forget the day _______ we worked together and the day ______ we spent together.
A. when; which B. which; when C. what; that D. on which; when
答案：A
解析：兩個先行詞the day都是表示時間的.名詞,但第一個空白處要填的關係詞在從句中作狀語,因此要用關係副詞when. 第二個空白處要填的關係詞在從句中作動詞spent的賓語,因此要用關係代詞which或that來引導定語從句.
2）當主語為物時，不能用what
3）there be句型中，指人用who指物用that。
4）當主句中缺少主語或表語時，用the one。
5）當出現先行詞+介詞時，關係詞只能用whom或which
6）當出現先行詞+介詞時，注意判斷介詞與從句謂語是否有關係，以確定為定語從句
