Period 4: Grammar
学习目标：
1. 掌握非限制性定语从句和定语从句的缩略形式
2. 体会非限制性定语从句和定语从句的区别
3. 利用例句归纳出语法规则
学习重点：掌握非限制性定语从句和定语从句的缩略形式
学习难点：利用例句归纳出语法规则
课前预习
使用说明与学法指导：
1. 利用例句归纳出语法规则
2. 15分钟之内完成
预习自测：
观察下列从Reading and Vocabulary中选取的句子，体会非限制性定语从句的用法。
①The power of the Yangt ze River，which is the world's third longest river，h as been harnessed by the Three Gorges Dam.
②The Three Gorges Dam，which is the biggest construction project in China since the building of the Great Wall and the Grand Canal，has been built to control flooding and provide hydroelectric power for the central region of China.
③Sun Yatsen，who was the leader of the 1911 Revolution，first suggested the idea of a dam across the Yangtze River in 1919.
