学人教版必修三Unit 4 AstronomyThe science of the stars Period2 Learning points（3页word版）.docx

2019学年度人教版必修三unit 4 astronomy-the science of the stars period2 learning pointsthe emphasis of this period will be placed on the important new words and sentence patterns in the parts warming up, pre-reading, reading and comprehending.important points: enable students to grasp the usages of such important new words and expressions as exist, puzzle, in time, in ones turn, prevent. from; get students to master the patterns “the earth became so violent that it was not clear whether the shape would last or not.” and “so whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved.” difficult points: 1). let students learn the usages of the expression “prevent.from.; 2). enable them to learn the sentence pattern “it is(not)+ adj. +that ( whether).”; 3). get them to understand some difficult and long sentences. knowledge aims: get them to learn the following sentence patterns:what it was to become was uncertain until between 4.5 and 3.8 billion years ago when the dust settled into a solid globe. (be to do; what-clause as the subject) the earth became so violent that it was not clear whether the shape would last or not. (so . that; it is / was not + adj. + whether-clause) what is even more important is that as the earth cooled down, water began to appear on its surface. (what-clause as the subject; that-clause as the predicative) it was not immediately obvious that water was to be fundamental to the development of life. (it is / was (not) + adj. + that) so whether life will continue on the earth for million of years to come will depend on whether this problem can be solved. (whether-clause as the subject; depend on + whether-clause as the object) step 1 revision check the homework exercises. ask some students to talk about how life began on the earth. step 2 reading and findingget students read through warming up, pre-reading, reading and comprehending to underline all the new words and expressions or collocations.step 3 practice for useful words and expressionsturn to page 28. go through the exercises and then do them by themselves.step 4 studying important language points1. according to: as stated by sb. or in sth.according to john, you were in edinburgh last week.you have been in prison six times according to our record.2. it is not clear how gold was found there.it is hard to understand why there is gravity. 3. in time: sooner or later; eventually in / out of time (sth.) be to (do): something will definitely happen, or it must happen you will succeed in time. she will be back in time to prepare dinner. the audience clapped in time to the music. she is to be honored for this great work.they said goodbye, little knowing that they were never to meet again.4. allow + n. / pron. / doing; allow sb. to do sth.5. exist: be real or actual; have beingthe roman empire existed for several centuries.contradictions exist everywhere.salt exists mostly in sea water.so poor they can hardly exist.one can not exist without air.6. be different from: not like someone or something else in one or more wayscity life is different from country life.7. give birth to: produce youngshe gave birth to a healthy baby last night.marks idea gave birth to communism.8. in ones turnin turn: one after the other; in successionby turn: one after the other; in rotation he has become monitor in his turn. the girl called out their names in turn. we did the work by turn. 9. prevent.from: stop or hinder sth. / sb. nothing can prevent their plan from being carried out. 10. depend on (sth. else): something might only happen or be true if the circumstances are right for it our success depends on whether everyone works hard or not. step 5