3、倒序相加法：如果一个数列{a}，与首末两项等距的两项之和等于首末两项之和，则可用把正着写和与倒着写和的两个和式相加，就得到了一个常数列的和，这一求和方法称为倒序相加法。特征：a_n+a₁=a_n-1+a₂通常，当数列的通项与组合数相关联时，那么常可考虑选用倒序相加法，(等差数列求和公式)

2、分组求和法：在直接运用公式求和有困难时常，将“和式”中的“同类项”先合并在一起，再运用公式法求和(如：通项中含因式，周期数列等等)

1、 公式法：⑴ 等差等比数列的求和公式， (2)

2. Report a thing recently happened in your neighborhood or in the local area.

1. Ask the students to interview a student of Senior Grade three and write a report about their present study and life.

3. Do Exercise3 to choose Ss’ understanding.

The primary source is the Garlic Wars because it was written at the time. I think Plutarch Life of Julius Caesar and Shakespeare’s play about Julius Caesar will have more opinion than fact because they were written long after the events happened.

StepⅣ Summary and Assignment

Today we’ve learned writing and printing process for an aticle and what is a primary source and what is a secondary one. These are very important for your future work if you want to be a reporter. Today’s homework:

2.　 Ask Ss to read the whole text again in detail and do the True or False questions on blackboard.

1. When we read about Jia Sixie in our textbook we are reading a primary

source.

2. As we watch the news on TV, the person presenting the programme in the

studio is the secondary source.

3. Photographers sometimes are both primary and secondary sources.

4. Knowing the difference of primary and secondary sources can help us decide what is a fact and what is an opinion.

5. Often facts and opinions are mixed in any report.

Keys: FTFTT

Tips

A primary source depends on: The person who has written the news should be there at the time.

Primary sources and secondary sources are very important for finding out the truth. The closer a person is to the event they describe in time or geographically, the more likely they are to be accurate.

1.　　 　Ask Ss to turn to page65 and read the passage as quickly as they can to get the main idea of the passage. (Answer: The passage tells us what a primary source and a secondary source are and the difference between them.

3.　　　 Then let the Ss make full use of their imagination to complete Ex2.

Step Ⅲ Extensive Reading (P 65)

2.　　　 Scanning: Ask Ss to read the passage again and try to answer the questions as listed on the screen.

Questions:

1)　　 What is Zhou Yang’s first task?　 (Answer: His first task was to write his story)

2)　　 How many people read his article before it was ready to be processed into film negatives? Who were they?　 (Answer: Before it was ready to be processed into film negative, an editor from his department, the copy-editor, the native speaker, the chief editor and the new desk editor read his article.)