Unit 3 Section Ⅲ GRAMMAR 限制性定语从句与非限制性定语从句-2021-2022学年新教材高中英语选修第一册【金版新学案】教师用书（北师大版）

Section Ⅲ GRAMMAR——限制性定语从句与非限制性定语从句 用适当的关系词完成下面教材中的句子并体会它们的语法特征 1．Extinctions，where entire species are wiped out，are not unusual in our Earth's history. 2．In the last 500 million years，there have been five times when life on Earth has almost ended. 3．These include the third mass extinction，known as the“Great Dying”，which killed 90% to 96% of all species. 4．And the fifth event，which occurred 66 million years ago, caused the death of the dinosaurs. 5．Although it is not unusual for species to die out naturally，the rate at which this is now happening is cause for concern. 6．A 2015 study by scientists who/that were based at Brown University and Duke University in the US，looked at how quickly species die out due to natural causes，that is, the“background extinction rate”． 7．There is a long list of reasons why so many species are dying out：air and water pollution，forests being destroyed, factory farming and overfishing. 8．For example，we need to take steps to save endangered species，including setting up special areas where plants and animals can be protected. 知识点1　定语从句的分类及定义 起定语作用，修饰某一名词或代词，或修饰整个主句的从句叫作定语从句。被定语从句修饰的词称为先行词。定语从句一般置于先行词之后，由关系代词或关系副词引导。引导定语从句的关系代词有which，that，who，whom，whose；关系副词有when，where，why。 1．限制性定语从句：对先行词起修饰限制的作用。 ·He is a teacher who works in our school. 他是一名在我们学校工作的老师。 2．非限制性定语从句：对先行词起补充说明作用(先行词与定语从句之间有逗号隔开)。 ·Beijing, which is the capital of China，is a beautiful city with a long history. 北京是中国的首都，是一座有着悠久历史的美丽城市。 比较：He has two sons, who work in the same company.(He has only two sons.) 他有两个儿子，他们在同一家公司工作。(他只有两个儿子。) He has two sons who work in the same company.(Perhaps he has more than two sons。) 他有两个在同一家公司工作的儿子。(也许他有不止两个儿子。) 知识点2　定语从句中关系代词和关系副词的用法 关系代词和关系副词有连接先行词和从句，以及指代先行词并在从句中充当语法成分的三重作用。关系代词与关系副词的作用及用法如下： 关系词 先行词 在从句中的作用 例句 who 人 作主语(不可省略)、宾语 The boy who is standing there is my cousin.站在那儿的那个男孩是我的表弟。 whom 人 作动词宾语或介词宾语(可省略) The man(whom) you met yesterday was Mr Smith.你昨天见的那个人是史密斯先生。 whose 人或物 (＝of whom/of which)作定语 He lives in a room who