____
如图是农田和草原连接的物质循环图,请据图回答问题:
如图是汽车、摩托车油量表(实际上就是电流表)原理示意图,R′是定值电阻,R是滑动变阻器,则( )
——Do you think Peter is free today?
——__________. He is really busy preparing(准备) for the coming test these days.