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课件网) Unit 9 Human Biology Lesson 1 Grammar Focus To practise using verbs in the perfect tense. Learning objectives Watch the video. What’s the main idea Do you think cloning is a good idea Use what you have learnt to try to persuade someone to accept your point of view. Views It’s a good idea: It’s a bad idea: the potential of cloning scientists’ devotion Einstein’s quote … clones’ health problems moral concerns Einstein’s quote … Revision Cloning is a good idea Cloning might lead to cures for various diseases and may also offer clues on how to prevent the aging process. Besides, cloning can change animals’ genes to suit research needs so as to save research time, produce more accurate results and lead to more effective treatments. At the same time, it also reduces the number of animals required for testing. So it benefits not only mankind but also animals in a way. According to Einstein, science is just a tool. So, we should regulate the way we use tools instead of giving them up. Cloning is a bad idea Clones always develop a similar pattern of health problems and die at an early age, which is an unsolved problem. Besides, cloning raises moral concerns. Some believe it is bound to lead to cloning of other species. The identity of clones is also questioned. Are they objects or individuals with identity Will the technology be abused by some organisations According to Einstein, used in a wrong way, useful tools can also kill. So, we should stop cloning so as to avoid the potential problems. Do you think cloning is a good idea In the last few years, China has made great achievements in environmental protection. The government has closed some heavily polluting factories down since 2012. So the air has become much cleaner to breathe so far. Chinese culture has become an interest for people all over the world since the Shanghai Expo and many foreigners are discovering the history of China. Besides, the Belt and Road Initiative has improved connection among the countries. China has become one of the most responsible global leaders the whole world has seen. Read the passage quickly. Underline the present perfect tense and circle time adverbials. Observing 现在完成时是过去的动作或状态持续到现在，对现在造成的影响，可能持续发生下去。其构成为：主语+ have/has +动词-ed形式。 现在完成时 1. 强调过去发生的动作对现在产生的结果或影响。 用法 past now Yesterday, we cleaned the classroom. Now, the classroom is clean because we have cleaned it. Exploring the rules 2. 强调动作或状态发生于过去一直延续到现在，且有可能继续下去，与表示持续的时间状语连用。表示持续动作或状态的动词多是延续性动词。例如： past future now came live has lived Daniel has lived in Beijing since he came to China. 3.现在完成时往往同表示不确定的过去时间状语连用，如already, yet, just, before, recently, still, lately等标志词。例如： He has already got a chance to go abroad. 4. 现在完成时常常与表示频度的时间状语连用，如often, sometimes, ... ...
