Unit 6 When was it invented? I. 单元核心重点 （1）一般过去时的被动语态 1. When I called the bus service, I _______ （tell） that there was no more bus. 2. I saw you hang out with Jane last week.（改为被动语态） You _____ _____ _____ _____ _____ with Jane by me last week. （2） be used to do/doing, be used for doing 1. I have been used to ______（eat） Chinese food since I came to China. 2. These machines are used to _______ （cut） down trees. 3. The sky lanterns were used _____ asking for help in ancient times.