Unit 4 Period 3 Discovering Useful Structures课件-教案课件-高中英语必修三

Unit 4Space ExplorationPeriod 3Discovering Useful Structures人教版本 必修三Lead-inWhat Powers a Spacecraft?Spacecraft have instruments to help them take pictures and collect information in space.But they need electricity to power those instruments and send the information back to Earth.Where does the power come from?Lead-inWhat Powers a Spacecraft?A spacecraft generally gets its energy from at least one of three power sources:the Sun,batteries or unstable atoms.To choose the best type of power for a spacecraft,engineers consider where it is traveling,what it plans to do there and how long it will need to work.Lead-in“to”New wordsThey charged the accident to the lack of experience.Please call before you come,otherwise we might not be home.or elsedifferentlyin other waysnot have sth.not have enough of sth.New wordsIt goes beyond our research.These materials can be recycled into other packaging products.Current success does not mean success in the future.save for reuseuse again differentlyreuse sth.pastexceptimpossible forexisting nowvalidflow of water or airNew wordsWe have provided sufficient information to you on this issue.Let them figure out the answer without you.enoughwork sth.outdecideLets playLets play1.Be modest,_ you will lag behind.2._ of food and supplies caused disaffection among the soldiers.3.They _ empty tins so as to use the metal.4.The contents go far _ the title.5.Even though they are a step in the right direction,our_ processes are not enough.6.They had no evidence _ to hold him.7.Father is trying to figure _ his tax.otherwiseLackrecyclebeyondcurrentsufficientoutLets learnLook at the following sentences and focus on the italicized infinitives.In pairs,discuss their functions and meanings.1.I trained for a long time to fly airplanes as a fighter pilot.2.As we all know,an astronaut needs to be healthy and calm in order to work in space.3.First of all,you must be intelligent enough to get a related college degree.4.Some scientists were determined to help humans realize their dream to explore space.5.On 12 April 1961,Yuri Gagarin became the first person in the world to go into space.Rewrite the sentences using infinitives or“in order to/so as to+do”.Change the italicized parts accordingly.1.In 2003 Yuri Malenchenko became the first person who got married in space.In 2003 Yuri Malenchenko became the first person to get married in space.2.In space,astronauts collect all dirty water so that it can be recycled for later use.1.In space,astronauts collect all dirty water so as to recycle for later use.E.g.3.Mankind has always been curious about the universe and many people,have dreamt that one day they would fly into space.Mankind has always been curious about the universe and many people to dream that one day they would fly into space.4.Astronauts bones and muscles can get very weak in space due to the lack of gravity,so they need to exercise every day,which will help them stay healthy.Astronauts bones and muscles can get very weak in space due to the lack of gravity,so they need to exercise every day in order to help them stay healthy.5.Astronauts have to use tape to stick everything down while working in space because everything would float off otherwise.Astronauts have to use tape to stick everything down to work in space because everything would float off otherwise.6.During a spacewalk,astronauts have to move slowly so that they can keep their bodies under control.During a spacewalk,astronauts have to move slowly so as to keep their bodies under control.Complete the passage with the correct forms of the verbs in brackets.Sending people to other planets or even beyond the solar system is not an easy goal _(achieve).One of the problems is that the trip would take over two years _(get)to the closest planet,Mars,and back.Although light is the fastest thing _(know)in the universe,it could take more than four years to reach the nearest star system.Will scientists figure out a way _(store)sufficient food and water for the long journey?to achieveto getto knowto storeComplete the passage with the correct forms of the verbs in brackets.Is it possible to travel faster than light?No one knows the answers yet.However,space scientists never give up.They are experimenting with growing crops in space so as _(help)astronauts get enough food on longer journeys through space.to helpInfinitives做主语做主语不定式置于句首不定式置于句首To get there by bike will take us half an hour.To make up for lost time is not possible.To lean out of the window is dangerous.To save money now seems impossible.用用it作形式主语，作形式主语，把真正的主语不定把真正的主语不定式置于句后式置于句后Its our duty to take good care of the old.How long did it take you to finish the work?It seemed impossible to save money.作宾语作宾语I happen to know the answer to your question.The question is how to put it into practice.I find it difficult to learn English well.作补语作补语Father will not allow us to play on the street.We believe him to be guilty.The book is believed to be uninteresting.to see1.The driver failed _(see)th