... bottles UNIT 16 : MAN AND THE ENV IRONMENT Period 99: B- (B2, 4) We should save water UNIT 16 : MAN AND THE ENV IRONMENT Period 99: B- (B2, 4) We should keep off grass UNIT 16 : MAN AND THE ENV ... UNIT 16 : MAN AND THE ENV IRONMENT Lesson 4: B- Population (B2, 4) We shouldn’t leave trash UNIT 16 : MAN AND THE ENV IRONMENT Period 99: B- (B2, 4) We shouldn’t cut down/damage the trees UNIT ... trash in the country e/ Keep off the grass f/ Save water g/ Collect paper h/ Collect bottles and cans UNIT 16 : MAN AND THE ENVIRONMENT Period 99: B- (B2, 4) Now match the rules with these signs...