(
课件网) Unit 3 Conservation Lesson 1 The Sixth Extinction(2) To learn about and practise relative clauses—defining and non-defining clauses Learning objective What is the function of the underlined clause in this sentence If a sixth mass extinction occurs, scientists who have studied the issue believe that up to three quarters of all species on Earth could die out. 作定语 起修饰作用 定语从句 Activate Relative Clauses 定语从句 A relative clause is a clause that usually modifies a noun or noun phrase and is introduced by a relative pronoun (which, that, who, whom, whose), a relative adverb (where, when, why), or a zero relative. 定语从句是由关系代词或关系副词引导的从句，其作用主要是作定语修饰主句中的某个名词或代词，相当于形容词。 Activity 1: Read the sentences and discuss the similarities and differences of them. 1. Extinctions, where entire species are wiped out, are not unusual in our Earth’s history. 2. These include the third mass extinction, known as the “Great Dying”, which killed 90% to 96% of all species. 3. A 2015 study by scientists who were based at Brown University and Duke University in the US, looked at how quickly species die out due to natural causes. 4. If a sixth mass extinction occurs, scientists who have studied the issue believe that up to three quarters of all species on Earth could die out. 5. We need to take steps to save endangered species, including setting up special areas where plants and animals can be protected. Discover 1. Extinctions, where entire species are wiped out, are not unusual in our Earth’s history. 2. These include the third mass extinction, known as the “Great Dying”, which killed 90% to 96% of all species. 3. A 2015 study by scientists who were based at Brown University and Duke University in the US, looked at how quickly species die out due to natural causes… 4. If a sixth mass extinction occurs, scientists who have studied the issue believe that up to three quarters of all species on Earth could die out. 5. We need to take steps to save endangered species, including setting up special areas where plants and animals can be protected. Similarity: Each sentence contains a relative clause. Differences: In sentence 1 & 2, the relative clause is separated from the main clause by a comma. In sentence 3, 4 & 5, it is not. Activity 1: Read the sentences and discuss the similarities and differences of them. 1. Extinctions, where entire species are wiped out, are not unusual in our Earth’s history. 2. These include the third mass extinction, known as the “Great Dying”, which killed 90% to 96% of all species. 3. A 2015 study by scientists who were based at Brown University and Duke University in the US, looked at how quickly species die out due to natural causes… 4. If a sixth mass extinction occurs, scientists who have studied the issue believe that up to three quarters of all species on Earth could die out. 5. We need to take steps to save enda ... ...
