unit 1 great scientists period 3 using language learning aims: 1. enable the students to learn about the development of astronomy. 2. learning about copernicus’ revolutionary theory. important point: to grasp some important and useful words, expressions and sentence patterns. difficult point: to improve the skills of reading. 使用说明及学法指导：1. 通过阅读课本p30，完成预习案。2. 完成时间：20分钟。预习案 previewing case task 1 read the text and match the main idea of each paragraph para.1 the result of copernicus’ study para.2 the procedure of copernicus’ study para.3 copernicus’ theory replaced the christian idea and proved correct para.4 the background of copernicus’ study
