Unit 4 Global Warming Period 2 Language Points
Learning aim ：Learn and grasp the usages of some important new words and expressions.
Learning important point： Use some useful words and expressions correctly.
Learning difficult point： Make sentences after the useful sentence patterns.
使用说明及学法指导：1. Discussing, summarizing and practicing 2 .Cooperative learning
使用说明及学法指导：1. 通过阅读课本P25-27，完成预习案。2. 完成时间：30分钟。
