Unit 13 We’re trying to save the earth!SectionA (3a-4c)I. 单项选择：（BC 层学生必做，A 层选做或不做）( )1. ---How long _________ the film _________? ---For about ten minutes.A. did; beginB. has; begunC. has; been onD. has; been( )2. ---Hello, Jack. Haven’t seen you for long. I’m callin...
