2019学年度人教版必修三Unit 4 Astronomy-The science of the stars Period2 Learning points

　The 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 one`s 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 finding

　Get 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 expressions

　Turn to page 28. go through the exercises and then do them by themselves.

Step 4 Studying important language points