Unit 12 Art and literature
who is the man that is standing by the door?
which of the two cows that you keep produces more milk?
（3）限定性定語從句和非限定性定語從句
限定性定語從句是句中不可缺少的組成部分，主句和從句之間不用逗號分開。而非限定性定語從句是對主句先行詞的補充說明，沒有從句不影響主句的意思完整。一般用逗號把主句和從句分開。不用關系代詞that。非限定性定語從句的關系代詞有時可以代表整個主句的含義，在非限定性定語從句中，作賓語的關系代詞不能省略。
例：the man who was driving the car was drunk. 開車的那人喝醉了。
this is the place where the three roads meet. 這是三條路交匯的地方。
the house whose windows are broken is mr. smith’s. 窗戶破損的房子是史密斯先生的。
i have two sisters, who are both students. 我有兩個妹妹，她們都是學生。
i have lost the pen, which i like very much. 我弄丟了那支鋼筆，是我非常喜歡的那支。
tom broke his eyeglasses, which made his mother quite angry. 湯姆打碎了自己的眼鏡，這使他媽媽非常生氣。（關系代詞which代表湯姆打碎眼鏡這件事）
（4）as引導的定語從句
① as用作關系代詞和關系副詞引導限定性定語從句，并在從句中作定語、表語或狀語，構成the same…as…, such…as…等結構。
例：i like the same book as you do. (as作賓語)
i shall do it in the same way as you did. (as作狀語)
i want to have such a dictionary as he has. (as作賓語)
② as引導非限定性定語從句。as在定語從句中作主語、表語或賓語，這個定語從句是說明整個句子，它可以放在主句之前。
例：as we all know, he studies very hard. (as作賓語)
as is known to all, he is the best student in our class. (作主語)
常用的這種類似插入語的句式有as is said above, as is known to all, as it is等。
注意：關系代詞在從句中作主語時，從句的謂語動詞的人稱和數必須和先行詞保持一致；關系代詞which和as在定語從句中的區別是：which不能放在句首，而as則可以；在句中時，as有“正如”、“就像”之意，而which沒有。