人教版必修3-Unit-4-How-Life-Began-on-the-Earth学案.doc

人教版必修3 Unit 4 How Life Began on the Earth学案学习目标: Learning the test （学习课文）教学重点： Get the main idea of the text (了解文章大意)课前准备 请同学们提前阅读学案内容，了解课堂上要完成的任务，（1）准备17导学案(2) 课本Page 25-26的课文Teaching Steps ；（教学步骤）Step 1 Have a check （检查上节课的内容）Step 2 Learn the text of Page 25-26 (学习Page 25-26课文)1 Fast Reading (关注课文中的数字，找出所发生的事件)4.5-3.8 billion years ago _Many million years later_for 140 million years_65 million years ago_2.6 million years ago_2 Careful Reading （仔细阅读课文 归纳段落大意）Para（1）_（2）_( 3 ) _( 4 ) _(5) _3 Careful reading (细读课文 完成排序) A Insects and amphibians appeared B Dinosaurs appeared C The earth became a solid ball D Small plants grew on the water E Reptiles appeared F Plants began to grow on dry land G The earth was a cloud of dust H Water appeared on the earth. I Shellfish and other fish appeared J The universe began with a BIG BANGK Clever animals with hands and feet appeared L Mammals appeared_Step 3 Think（思考） Is it wrong or right to show films with dinosaurs and people together? Why? (在课文中找到合适的语句，或根据自己的理解回答此题)Step 4 A quit of the text (当堂检测，课文内容填空) The universe began with a _ .At that time , the earth was_.Then, the earth became _.After that, water appeared on the earth and_grew on the water . Then, shellfish and other fish appeared . Next, _began to grow on dry land and insects and amphibians_. Later, reptiles and dinosaurs appeared. Last, clever animals _appeared and spread all over the earth. Thus, the human become the most important animals on the earth. However, they are not looking after the earth well. They are putting too much carbon dioxide into the _, which prevents heat _ escaping from the o space. So whether life will continue on the earth for millions of years to come will _on whether this problem can be solved.Step4 课文知识点 1. In our solar system eight planets circle around the sun.在我们的太阳系里，八大行星绕着太阳运转。solar system 太阳系八大行星：Uranus（天王星） 、Venus（ 金星 ）、 Earth （地球）、 Mars（火星 ）、Mercury （水星）、Jupiter （木星）、Neptune（海王星）、Saturn（土星）2. Can you match the names with the planets?Match to/with 将配对,与相匹配Match the words with the destinations. 把这些词与释义相连。3. The origin of life on earth is a question that interests astronomers.地球上生命的起源是一个使天文学家感兴趣的问题。the origin of life 生命的起源 that interests astronomers 定语从句4. According to a widely accepted theory, the universe began with a “BigBang”(that threw matter in all directions.) 一种普遍为人们所接受的理论是：宇宙起源于一次大爆炸，这次大爆炸将物质投射到四面八方。a widely accepted theory 一种普遍为人们所接受的理论begin/start with 以开始 end up with 以结束A thousand Li journey starts/begins with the first step.千里之行，始于足下。5. The earth was still a cloud of dust.(一团尘埃)6. What it was to become was uncertain until between 4.5 and 3.8 million years ago when the dust settled into a solid globe.随后它会变成什么没人能知道，直到38-45亿年前，这团尘埃才慢慢地形成一个固体的球状物。What it was to become 主语从句 be to do sth 常用来表示不可避免将要发生的事。As a young man he didnt know he was to win world fame later on.年轻时，他不知道自己日后会举世闻名。settle in/into sth 安顿下来；习惯于（新居）；适应（新工作）settle down 安静下来，平静下来7. It exploded loudly with fire and rock.They were in time to produce carbon, nitrogen, water vapour and other gases, which were to make the earths atmosphere.它（地球）猛烈的爆炸喷出了烈火与岩石，最终产生了碳、氮气、水蒸气和其它多种气体，从而形成了地球的大气层。in time 及时 最终，迟早You will learn how to do it in time.你迟早能学会做这件事。The doctor came just in time.医生及时地赶到了。which were to make the earths atmosphere.非限制性定语从句8.What is even more more important is that as the earth cooled down water began to appear on its surface.更为重要的是，地球冷却了下来，地球的表面就开始出现了水。What is even more more important 主语从句cool down 变凉，冷却下来 as （随着）后面加从句=with加名词或动名词As time goes by, I get used to the weather here.=With time going by, I get used to the weather here.随着时间的进展，我习惯了这儿的天气。9.It was not immediately obvious that water was to be fundamental to the development of life.水会对生命的发展起关键作用，这一点在当时并不是很明显。It is obvious that=It is clear that 很明显It is obvious that you are wrong.很显然，你是错误的。10.What many scientists believe is that the continued presence of water allowed the earth to dissolve harmful gases and acids into the oceans and seas.很多科学家相信，由于地球上长期有水存在，使地球得以把有害气体和酸性物质溶解在海洋里。What many scientists believe 主语从句that 引导的是表语从句 allow/permit sb to do sth 允许某人做某事allow/permit doing sth 允许做某事dissolve harmful gases and acids into the oceans and seas.把有害气体和酸性物质溶解在海洋里。 dissolveinto 把溶解在11.They produced young generally by laying eggs.它们一般是通过孵蛋而繁衍后代的。by doing 用于说明做某事的手段、方式。He used to make his living by painting.他以前是靠画画为生。12.They are putting too much carbon dioxide into the atmosphere, which prevents heat from escaping from the earth into space.他们把过多的二氧化碳释放到大气层中，这使得地球上的热不能释放到太空中去。which prevents heat from escaping from the earth into space.非限制性定语从句prevent/stop(from)doing sth 阻止做某事=keepfrom doing sthHis heart trouble didnt prevent him (from) going to class the next day.他的心脏病没能阻止他第二天去上课。Nothing can prevent their plans (from) being carried out.什么也不能阻止他们的计划得以实施。13.So whether life will continue on the earth for millions of years to come wi