二、活塞环:分成气环和油环两大类。 (一)作用: 1、气环:(1)密封(防止燃气漏入曲轴箱);气环是主要作用,是传热作用的前提. (2)传热(将活塞头部吸收的70%~80%的热量传导给气缸壁)

Teaching Outline Pre-reading Questions Background Information Passage AnalySIs style and structure spelling word derivation language points useful expressions

Unit 5 Language structures Dialogue 1 Dialogue 2 Reading1&2

Understanding the Title The Jazz Scene means A. The Jazz performance B. The background of Jazz C. The noisy, heavily rhythmic Jazz music D. Introduction to Jazz

General organization Comprehension Language points Interaction activity

Go back to sth. Return to an earlier point in space or time How far does your memory go back? 让我们回到原来正在讨论的问题上去吧 Let's go back to the subject we were discussing? ·若要探讨爱尔兰问题的起源我们得回到几百年前. To trace the origins of the Irish problem, we have to go back over three hundred years

Teaching Outline Duty report dictation Background information Pre-reading questions Passage analysis style and thesis development writing techniques word derivations language points Going beyond the text(group activities) Homework Weekly quiz

Pre-reading Questions 1. Name several pollutants 2. Who causes pollution? 3. Why is pollution one of the most serious problems that man faces these days? 4. Why is the pollution problem complicated? 7. 5. How can pollution be gradually reduced? 6. When did man begin to pollute his

Pre-reading Questions 1. What does the \Green Revolution\ refer to? 2. Why did various writers predict that there would be widespread famine? 3. Name some countries with serious food shortages. 4. What is \miracle rice\?

abUs公共汽车站旁的候车棚 a bomb~防空洞 A·seek- for the night找个过夜的地方 In the storm we took (found)- under a tree The basic necessities of life are food Clothing and