【同课异构】2018-2019学年人教版高一英语必修3课件:Unit 4 Section Two
【同课异构】2018-2019学年人教版高一英语必修3课件:Unit 4 Section Two第3页

system n. 系统;体系;制度 They have a warning system in the house. The legal system are quite different in these countries. solar system 太阳系 systematic adj. 有系统的;系统化的