Inventions3高二英语课件

Unit 18inventions 1p 2pr 3c 4gtoFour great inventions in the history of chinaPAPERtoPrintingtocompassestogunpowdertoLesson 78PAPER1 What did people use for keeping records in the beginning?2 Whats the main idea or the topic sentence of each paragraph?Text1 What did people use for k，